I can’t keep a bike inside my place in Columbia Height (no room and too many stairs for me to deal with), so I don’t own one. I wouldn’t lock one outside.
I recommend Capital Bikeshare–which I use frequently–for people who want to use biking the way they would use public transportation. I see bikeshare as another transportation option in my arsenal when deciding how to get somewhere–I choose between bike, bus, or metro depending on time of day, where I’m going, and the weather. If you want to use a bike more for exercise or exploring, I would get your own bike. Also, if you plan on 100% relying on a bike to commute, don’t rely on bikeshare. I live in Columbia Heights and can usually get one if I leave the house by 8AM, but if I’m running late, I have to take the bus as all the bikes are gone. Same when I have to work late.