Do you keep an exercise log? Should I keep doing mine?

[bfit]

Do you keep an exercise log no matter what kind of exercise you are (or are not) doing? I've kept a log for years, but now I can't run any more or do high impact activities ever again because of the permanent effects of an injury. It doesn't seem like there's much of importance to write in the log any more, and I haven't written anything down since the New Year started, and I'm thinking of just giving it up. What do you do? And what do you think?