LeanFIRE vs FatFIRE: How Do You Track Two Completely Different Lifestyles in One Ledger?

General
1

I need your help thinking through something I’ve been wrestling with for months.

When I started my FIRE journey three years ago, the goal was crystal clear: LeanFIRE at $30K/year expenses. Save aggressively, move to a low cost-of-living area (or maybe Portugal at $18K/year), and escape the 9-to-5 by age 38. Simple, achievable, freedom-focused.

But here’s what happened: I built these elaborate Beancount tracking systems, ran the numbers every month, watched my net worth grow… and started questioning whether I actually want to live on $30K/year for the next 40+ years. Now I’m looking at FatFIRE scenarios around $100-120K/year, which pushes my timeline out to age 50. Completely different target.

The Core Problem: These Aren’t Just Different Numbers

LeanFIRE and FatFIRE aren’t just about portfolio size—they’re completely different tracking philosophies:

My current LeanFIRE tracking approach:

  • Every $5 expense gets scrutinized (“did I really need that coffee?”)
  • Obsessive optimization of grocery costs, transportation, housing
  • Geographic arbitrage calculations (Portugal $18K vs Thailand $21K vs US $30K)
  • Emergency fund sized for lean lifestyle
  • Focus: minimize expenses, maximize savings rate (currently 62%)

What FatFIRE tracking would look like:

  • Income optimization becomes priority (side projects, salary negotiation, investments)
  • Tax efficiency matters more than expense cutting
  • Tracking quality of life metrics, not just dollars
  • Emergency fund 3x larger
  • Focus: maximize earning power, maintain lifestyle quality

My current life costs $75K/year. I’m tracking which expenses are “lean compatible” vs “fat lifestyle,” but it’s creating this weird cognitive dissonance.

My Beancount Dilemma

Right now I have one ledger tracking actual reality. But I need to model three scenarios simultaneously:

  1. Current reality: $75K/year, hitting FIRE in ~12 years
  2. LeanFIRE path: Cut to $30K/year, hit FIRE in 5 years
  3. FatFIRE path: Accept $120K lifestyle, hit FIRE in 15 years

I’ve been doing this manually with bean-query exports to spreadsheets, but it feels kludgy. I know Beancount’s forecast plugin exists, but I’m not sure it’s designed for this level of scenario planning.

Questions for the Community

For those tracking FIRE goals:

  • Do you use Git branches to test different lifestyle scenarios?
  • How do you separate “essential” vs “optional” expenses in your ledger? Separate accounts? Tags?
  • Anyone successfully track both lean and fat projections simultaneously?
  • What about geographic arbitrage modeling—how do you track “what if I moved to Portugal” scenarios?

For anyone who switched between lean and fat:

  • What made you change your target?
  • Did the tracking help you realize what you actually value?
  • Any regrets about aiming too low or too high?

My Real Numbers (Annual)

  • Current expenses: $75,000
  • LeanFIRE target: $30,000 (5 years to FI)
  • FatFIRE target: $120,000 (15 years to FI)
  • Current portfolio: $380,000
  • Savings rate: 62% of gross income

The math is clear. What’s not clear is which number represents the life I actually want to live.

The Emotional Cost Nobody Talks About

Here’s the thing nobody mentions: tracking two competing visions of your future is exhausting. Every spending decision becomes a referendum on your values. Buy the $200 concert ticket? That’s 0.67% of my LeanFIRE annual budget but only 0.17% of FatFIRE. Which “me” am I optimizing for?

Is there a middle path? Some kind of “RegularFIRE” at $60K that captures most of what I value without extreme frugality? Or is that just another way to delay making a real decision?

Would love to hear how others handle this in their Beancount workflows. Do you track multiple scenarios? Did you eventually commit to one path? How did you decide?

tl;dr: Started tracking for LeanFIRE ($30K/year), now questioning if I want FatFIRE ($120K/year). How do you track two completely different lifestyles in one ledger? Which one did you choose and why?

2

This really resonates with me from a different angle - I see this with my small business clients all the time.

I have clients who optimize purely for profit (the “LeanBusiness” approach) - minimal overhead, no fancy office, drive 10-year-old trucks, reinvest everything. And I have clients who prioritize lifestyle - nice office space, company vehicles, regular travel to conferences, comfortable margins. Neither is wrong, but they’re fundamentally different strategies that require different tracking.

Here’s what I’ve noticed: The clients who try to track both scenarios simultaneously often end up somewhere in the middle. I’m starting to think there’s a “RegularFIRE” sweet spot that most people eventually land on - not extreme frugality, not luxury, just… comfortable.

Practical Beancount suggestion

Have you considered using account hierarchies to separate this out?

Expenses:Lean:Housing     ; Bare minimum rent/housing
Expenses:Lean:Food        ; Grocery-only, no dining out
Expenses:Lean:Transport   ; Public transit, bike

Expenses:Fat:Housing      ; Nicer place, location premium
Expenses:Fat:Food         ; Includes restaurants, premium groceries
Expenses:Fat:Transport    ; Car payment, insurance, gas
Expenses:Fat:Lifestyle    ; Travel, entertainment, hobbies

Then use tags for actual spending: #essential vs #discretionary. That way you can query your current life and see what portion fits each model.

Real talk from the field

I had a client who planned for LeanFIRE, got there at 42, and realized he deeply missed two things: live music and nice meals with friends. Neither was “essential,” but removing them made him miserable. He went back to part-time work (BaristaFIRE) specifically to afford those two categories.

The tracking didn’t tell him that—actually living on $30K for six months did.

Question back to you: Have you tried living on your LeanFIRE budget for 3-6 months? Not just tracking it, but actually constraining yourself to $30K/year spending to see how it feels? That experiment might teach you more than any scenario analysis.

You might discover which expenses you genuinely value vs which are just habits. And that emotional data is just as important as the math.

3

I’ve been exactly where you are, and I want to share what I learned from going through this same process.

My story

Four years ago, I was tracking for LeanFIRE at $35K/year. Had elaborate spreadsheets modeling geographic arbitrage (Vietnam! Mexico! Eastern Europe!). The math said I could quit my tech job at 40 and live anywhere in the world on $3K/month.

Then I ran a 6-month “practice retirement” experiment while on sabbatical. Moved to Portugal, tracked every euro, lived the lean lifestyle.

What I learned: Geographic arbitrage wasn’t for me. I missed my friends. I missed the Pacific Northwest. I missed my real estate investing network. All the savings in the world didn’t compensate for feeling disconnected from my community.

Where I landed

I now target what I call “LeanishFIRE” at $50K/year - staying in the US, modest housing, used cars, but with room for the things that actually matter to me: local community involvement, occasional travel to see friends, and my woodworking hobby.

Sounds obvious in retrospect, but the tracking process was what taught me this. Cutting to lean forced me to discover what I actually value vs what’s just lifestyle bloat.

Beancount workflow for your scenario :+1:

Here’s what I actually do:

1. Main ledger = reality
My primary .beancount file tracks what’s actually happening. No projections, no dreams, just transactions.

2. Forecast files for scenarios
I use the forecast plugin with separate profiles:

  • lean.forecast - $35K/year baseline
  • comfortable.forecast - $50K/year (my current target)
  • fat.forecast - $80K/year (if I wanted more lifestyle)

The forecast plugin projects recurring transactions, so I can visualize each scenario’s cash flow.

3. Git branches for “what-if” experiments
When I want to test major changes (like the Portugal move), I create a Git branch:

git checkout -b portugal-experiment
# Model housing, expenses, tax implications in that branch
# Merge insights back to main, discard the branch if it doesn't work out

This keeps my main ledger clean while letting me experiment freely.

The philosophical insight :bullseye:

Your analytical approach is perfect for this decision. But here’s the thing: the number matters less than the clarity.

Whether you pick $30K or $120K, what matters is understanding why. The tracking process is teaching you about your values - that’s more valuable than hitting any specific number.

My advice

  1. Don’t over-optimize for a number that will change. Life happens. Health changes. Interests evolve. Kids happen (or don’t). The perfect spreadsheet model breaks on contact with reality.

  2. Track multiple scenarios for 6-12 months. See which one you naturally gravitate toward in your daily decisions. Your behavior will reveal your preferences.

  3. Test the lean lifestyle (Bob’s suggestion is spot-on). You can’t know if $30K is enough without trying it.

  4. Build in flexibility. Maybe the answer is: hit LeanFIRE in 5 years, then choose whether to keep working for FatFIRE or stay lean. Optionality has value.

You’re doing great by asking these questions. The fact that you’re thinking deeply about this means you’ll figure out the right answer for you - even if that answer changes over time.

Feel free to DM me if you want to see my actual forecast files or bean-query scripts. Happy to share. :blush:

4

As a CPA, I need to point out the elephant in the room: LeanFIRE and FatFIRE have completely different tax implications, and that should be part of your scenario planning.

Tax brackets matter enormously

LeanFIRE advantage ($30K/year):

  • Married filing jointly in 2026: 0% long-term capital gains rate up to ~$94,050 taxable income
  • With standard deduction (~$29,200), you can realize up to ~$123K in gross income and pay 0% on qualified dividends and LT cap gains
  • ACA marketplace subsidies typically available
  • Tax-efficient Roth conversion ladder opportunities
  • Potentially zero federal income tax if structured properly

FatFIRE reality ($120K/year):

  • You’re solidly in 15% (or higher) long-term capital gains brackets
  • Limited or no ACA subsidies
  • Need sophisticated tax planning: municipal bonds, qualified dividend optimization, tax-loss harvesting
  • Likely paying $15-25K/year in federal taxes alone

Geographic arbitrage tax warning

If you’re considering moving abroad (Portugal, Thailand), remember: US citizens owe taxes on worldwide income regardless of where they live. You get a ~$126K foreign earned income exclusion, but that doesn’t apply to investment income in retirement.

Plus, Portugal’s NHR (Non-Habitual Resident) tax regime has gotten less favorable, and Thailand is tightening tax rules on foreign-source income.

Beancount tracking suggestion

Tag your transactions by tax treatment, not just lifestyle category:

2026-03-15 * "Dividend from Vanguard"
  Assets:Checking           100.00 USD
  Income:Dividends         -100.00 USD
    category: "passive-income"
    tax-type: "qualified-dividend"

2026-03-20 * "Sold AAPL shares"
  Assets:Checking          5000.00 USD
  Assets:Investments:AAPL -4500.00 USD
  Income:Capital-Gains     -500.00 USD
    tax-type: "long-term-cap-gains"

Then you can query your actual tax burden under different withdrawal scenarios:

SELECT
  SUM(position) as total_gains
WHERE
  'tax-type' = 'long-term-cap-gains'
  AND year = 2026;

My recommendation

Model both scenarios WITH the tax burden included. Your $30K LeanFIRE might cost $30K after-tax (nearly zero federal), while $120K FatFIRE might require $145K gross withdrawal to net $120K after-tax.

That changes your portfolio requirements:

  • LeanFIRE: $750K (30K × 25)
  • FatFIRE: $3.6M (145K × 25)

The gap is even bigger than you thought.

Offer to help

I’ve built bean-query scripts that estimate tax liability under different withdrawal scenarios. If you’re interested, I can share them (or we could collaborate on making them more robust for the community). The FIRE tracking tools should include tax planning, not just expense tracking.

Let me know if you want to dive deeper into the tax optimization side of this question.

5

Wow, thank you all for the incredibly thoughtful responses. This is exactly why I love this community - you’re not just sharing Beancount syntax, you’re sharing real wisdom.

Responses to each of you

@bookkeeper_bob - Your account hierarchy suggestion is brilliant and embarrassingly obvious now that you’ve said it. I’m going to implement that this weekend. And yes, I absolutely need to do the 3-month lean lifestyle test. I’ve been avoiding it because I think I’m scared of what I’ll learn. Your client’s story about live music and nice meals really hit home - those are exactly two categories I’m not sure I want to cut.

@helpful_veteran - Your Portugal story is incredibly valuable. I’ve been romanticizing geographic arbitrage (“I’ll make friends anywhere!”) without honestly assessing whether I’d actually be happy disconnected from my Seattle community. The forecast plugin + Git branch workflow is exactly what I needed. Would absolutely love to see your actual files if you’re willing to share - I’ll DM you.

@accountant_alice - This is the wake-up call I needed. I’ve been doing all my math on gross withdrawal rates without properly accounting for taxes. You’re right that the gap is even bigger than I thought: $750K vs $3.6M is a 4.8x difference, not just “a few more years of work.” The tax-type tagging approach is genius - I’m implementing that immediately. And yes, please share those bean-query scripts! I think the whole community would benefit.

What I’m realizing

The tracking itself is teaching me about my values in a way that just thinking about it never did.

Here’s what I’m going to do:

  1. Implement Bob’s account hierarchy this weekend to see which of my current expenses fit “lean” vs “fat”
  2. Try a 3-month lean lifestyle experiment starting April 1st - actual $2,500/month budget constraint
  3. Set up Mike’s forecast plugin workflow with separate scenario files
  4. Add Alice’s tax-type tags to understand real after-tax withdrawal needs
  5. Track this as a project and report back in July: “3-Month Lean Experiment Results”

The insight I didn’t expect

You’ve all basically said the same thing in different ways: the number isn’t the point, understanding what you value is the point. The tracking is the teacher.

I think I’ve been treating this like an optimization problem (minimize years to FI) when it’s actually a values clarification exercise (what kind of life do I want to live?).

Community question

Would anyone be interested in a shared “FIRE scenario planning toolkit” for Beancount? Combining Mike’s forecast workflows, Alice’s tax queries, and Bob’s account structure into something documented and shareable?

I’m thinking:

  • Sample forecast files for lean/regular/fat scenarios
  • bean-query scripts for tax estimation
  • Template account hierarchies
  • Documentation on Git branching for scenario testing

If there’s interest, I’d be happy to start a GitHub repo and coordinate contributions. Let me know!

Thank you all again. This conversation has been worth more than a hundred blog posts. :folded_hands: