I haven't hurt him YET....
I hope I never do.. I've heard him scream and it's the stuff that nightmares are made of. Horrible sound.
I don't really have a schedule for trimming his nails... just whenever they seem to get long - I think my vet told me every 6 weeks or something, but I think since I cut so little off, I have to cut them a little more regularly than that. If you let them go for too long then the quick will grow as well, so you wont be able to cut as much off, you have to keep cutting tiny bits off and the quick will slowly retract back.
Be sure to have some styptic on hand just in case you happen to nick the quick, it'll stop the bleeding.
My apologies, I don't have the guilotene style, that's what my family used on our old dogs - I have this style (middle pair) which I guess is a scissor style:
http://www.renspets.com/mm5/merchant...y_Code=trimmer
You can kindof see in the picture the little stopper underneath...