Regarding the specific case of working in SV while living in SV vs. commuting from SF: I've lived in SV for about 9 years now. I know a lot of people who live

Regarding the specific case of working in SV while living in SV vs. commuting from SF: I've lived in SV for about 9 years now. I know a lot of people who live up in SF and commute to SV. I don't know how accurate this is, but my observation is that SF housing prices are >= SV. The people that live in SF and commute to SV universally do it because they would prefer to live in SF for one reason or another, rather than for financial reasons. When comparing what $x of housing will get you in SF vs. SV, the SF equivalent for the same price will have very different characteristics. The SV housing will likely be much newer and less unique than the SF housing, but it will also likely be in better condition than the SF housing. Another huge aspect is the length of that commute. It's 60-90 minutes each way, every day. Some people are much more OK with that than others- I personally couldn't do it. The big SV companies have generally nice buses with bathrooms and wifi, where you might be able to get work done and might even be comfortable, but even so that means 3 hours/day on a bus. A nice bus, but still- 3 hours/day on a bus is 3 hours/day on a bus. Now, some people will say that's great, because they use SF public transport and take the company bus to work and now they don't have to spend money on a car. In theory that sounds great, but what if you want a car? You're living in northern California, which I think is one of the most beautiful, varied, and interesting places in the world. Not owning a car means not being able to take off on a whim and go drive down Big Sur, or out to the desert, or Tahoe, or wherever. In theory a non-car-owner could rent a car when they want one and enjoy that lifestyle, but in practice most people end up sticking to destinations they can get to via public transit. That might not be a tradeoff everyone wants to make. Ah, one might say, but you can have it both ways! You can own a car and live in SF, and still enjoy the commuter buses. Well, get ready to spend several hundred dollars a month on a place to store your car that you only use for weekend jaunts, road trips, and whatever needs pop up. Now the housing that was $x in SV that included car storage will cost you $(x + y) in SF, where $y is the cost of a parking space. All of which is a long-winded way of saying that SF and SV cost about the same but it's very hard to do an apples-to-apples comparison of what $x will get you in either place. The choice comes down to how an individual assigns weights to the pros and cons of each locale.