I did two centuries last year - so I know I can do the distance ok. My main reason for doing them is to simply get in a LOT of base miles so I can lose weight. If I can achieve other goals at the same time, then that is a bonus. One goal is to do a century every month this year (which I hope to do), and the other goal is to finally do it in 5 hours (or less). Noble goals, and I hope ones thta will help to motivate me while my butt is aching out there on the bike.