Walk Score is a free website that measures the walkability of any address. The address will be given a walk score of 0 - 100, 100 being the most walkable.
The image above is the Walk Score map of our previous house in the Bay Area. It scored 95, aka "Walker's Paradise." I would show you the score of our SLO house but that wouldn't be responsible of me. However, I can tell you that it scored 80, aka "Very Walkable."
San Luis Obispo is known for being very walk-able and bike-able. In fact, I think that's one of the reasons that it's the happiest place in America.
I can't tell you how important it is to me that I can walk or bike everywhere. But that's just me -- not everyone wants to live that close to everything. Some people would rather not see their neighbors at all.