1) How much money do you need, on an on-going basis, to maintain your level of comfort/improved health/whatever you’ve been spending the money on? Think of this in terms of annual expenditure. Include all of your livings expenses in this.
1a) What can you do to decrease your annual income needs? This might be something big like relocating away from an HCOL area, removing superfluous spending (i.e., things that aren’t making you happy/healthier/etc.,) or optimizing current spending (do you have a big cable package that you don’t use, do you need a new smartphone every year or could you upgrade every 2 - 3 years, etc.) Take this away from the number is step 1) and you get variable A. Example: 150,000/yr.
2) What do you want to do post-FAANG, if anything, and how much will it pay? This number is B. Example: $75,000/year.
3) What are you current investment assets? This number is C. Example: $1,000,000.
4) How much investment income could they produce? For round number purposes, in the current investment environment, maybe start with a 3% withdrawal rate. This number is D. Example: 3%
A. B. C. D.
150000 - 75000 — (1,000,000 * 3%) = 45,000. D
45,000 / 3% = $1,500,000.In this example, you need to save/invest an additional $1.5M for your plan to be realistic, or change your expenses or post-FAANG income to alter the timeline. However long it will take to grow your assets by $1.5M — through additional savings from your FAANG income and returns on existing investments — is how long you need to stick it out at your FAANG job, or an equivalent high-stress/high-pay job — before jumping ship without suffering any loss from the benefit the high income provides.