I'm actually studying for the Bar Exam right now, so I don't get out as much as I'd like to. Maybe twice a month... maybe...
When I go, I typically go through 100 rounds of .45 ACP, and then shoot my little snub .22 until I get bored (about 100 more rounds usually does the trick). My pistol instructor tells me that shooting more than 50-100 rounds of the .45, at my beginning skill level, really doesn't do me any good, because the recoil will steadily "shred my nerves" and chip away at my ability to concentrate on the shot. I don't know if this is true, but I do notice that shooting 100 rounds of .45 makes me just as tired as mowing the lawn for about an hour.
Do you more experienced guys find that you can shoot more now than you could when you were a beginner?