[arbitrage314]

Actually, one small correction to your math.

You should adjust, for cost of living, only the part of your paycheck that you will be spending while living in that area.

E.g., supposed SF is twice as expensive as Dallas. If you make $100k in Dallas, and you typically spend $70k of it in Dallas while saving $30k (to spend later in life somewhere else), you would need to make $70k x 2 + $30k = $170k in SF (for an overall adjustment of 1.7) rather than $100k x 2 = $200k in SF (for an overall adjustment of 2).

Then again, if you're planning on living somewhere for the rest of your life, it's safe to assume that whatever money you make in that place, you'll also be spending in that place. Therefore, in that situation, multiplying by 2 would be correct after all.