I commuted without using a car for the better part of a decade, and over time, started doing many other tasks (small grocery runs, going out, etc.) without the car. My significant other had already quit driving, and since I rarely used the car, I sold it in March 2014. I bought a bicycle that was better suited to winters in western Wisconsin and a trailer.
Not using the car and then getting rid of it entirely was not a commitment so much as something that seemed reasonable for my household. I like cycling, and riding for everything rather than just commuting was not a big lifestyle change. Getting to work and getting the groceries was doable and even easy by bike; I've only used a backup a handful of times.
Circumstances change, and I'll be getting a vehicle (probably a large van) this summer. I still plan to do most everything by bike, but circumstances now warrant having an available vehicle as well.