Probably also needs some kind of purchasing power parity adjustment - divide by the cost of a specified size of house within a reasonable commuting distance, for example.
I completely agree with this. Throughout my career people have always spouted the same crap about "cost of living" for an area. Unless you're barely surviving paycheck to paycheck, or your household is poor to lower-middle class (which imo should not be a common case for a professional Software Engineer), the majority of your spending should not location specific. Rent/Mortgage monthly payments are often recommended to be limited to about 28-30% of your gross income. It is almost always in your best interest to go for the higher income number (and location).
I would disagree. I don't really see what people are spending money on? Everyone I know working in technology have pretty much bought everything they ever wanted in terms of electronics, clothes, equipment and vacations long ago. Most people could afford a sports car by 30 if they wanted to. Unless you have very expensive taste these things really aren't that expensive. What is expensive is space (housing, vacation home, workshop), time (education, sabbaticals, hobbies) and fluffy things (security, love, prosperity). Sure, housing might only be some percentage, but it is that percentage for the a large part of your life.
