I have a list of songs on a post-it note affixed to my guitar. I try to run through the list at least once a day. If I play it pretty smooth, I move on to the next one. If I mess it up, I try to work on any rough spots and play it again until I get it smooth. But after about 45 minutes, I seem to start losing concentration. I start making careless mistakes. Does anyone else have this problem, and if so, how do you deal with it?

Randall