How to convince people to use revision control

[Dave Smith]

I am a huge fan of revision control for software development. Until 
recently, I thought every one else was too. For the past couple years, 
I've been working with someone who begrudgingly uses CVS and Subversion 
and only commits about once a month (on good months). The ill effects of 
such a practice seem obvious to me, though I have a hard time voicing 
them to my co-worker. To date, my attempts at convincing him to do at 
least daily commits have fallen on deaf ears. He claims that his manual 
backups are sufficient, and that for a one-man project it doesn't really 
matter. Can you give me any suggestions on how I can convince him to 
join the rest of the civilized world and use revision control daily, 
without being a jerk and going over his head?

Thanks in advance!

--Dave