As a newly graduated Site Reliability Engineer who's working in the Bay Area. I'm living and working in Sunnyvale, my expenses are way lower than expected, I was able to get a house a 20 minute bike away from work. I get a free caltrain pass, so I really don't need a car. I think the "cost of living" adjustment here is unfair. Sure, living in SF proper can cost you upwards of 8k-9k a month but there are MUCH more reasonable apartments where most of the tech jobs are in the South Bay area.
Simple COL adjustment factors give you a baseline, but they don't really work reliably beyond straightforward apples-to-apples comparisons. It probably works pretty well for comparing house/condo and transportation choices between one suburban location and another where rents are modest and you need a car.
But doing a naive COL comparison between, say, Manhattan and Columbus, Ohio just isn't going to capture the lifestyle differences and tradeoffs.
Do you have a family and rent your own place or do you share accommodation? That is a huge factor. I have single friends who pay $600 rent as opposed to me paying $3000.
