I'm one of the main developers of LilyPond, which takes a fair amount of time. As discussed previously, I'm trying to keep it under control setting limits on the time I spent on it. I slipped up during the summer, so as of 1 Aug, I'm restarting these limits. This time it's 10 hours per week. And I modified some software to help me!
Is 10 hours ok? Well, it sounds like a lot... I mean, that's 40 hours -- a week of full-time work -- each month! But look at it this way: if I was a serious amateur violinist, I'd practice for an hour a day, plus maybe a two-hour orchestra rehearsal once a week, and maybe a one-hour quartet rehearsal. Hey, that's 10 hours! So I figure that 10 hours a week is a decent amount of time for a "serious hobby".
I modified TimeTracker, a simple python script for timing various projects. The program came from:
$ tt.py mod 1 30 Added 30 minutes to task 1.
This addition is useful when I've been working on my desktop computer -- my time-keeping is done on my laptop, so I just need to remember that I spent 30 / 45 / 90 minutes working on the desktop, and add that time to my laptop's record when I have a chance.
If other people find this program useful, I might clean up the documentation a bit. The program is in the public domain (following the original author's decision).