I have over 30,000 rounds on my 1995 Hi-Power and since I kept a log book, I have a decent idea of round count and parts replacement on it:
http://thefiringline.com/forums/showthread.php?t=7205
Short version: I didn't have to replace ANY parts until 13,000+ rounds and then the first part that broke was an aftermarket part I added to "enhance" the pistol, not a factory part. The first factory part to break happened around 16,000 and the first factory part to break that affected function happened around 20,000.
I'd just add that as long as you keep up with maintenance and replace broken parts, the Hi-Power is boringly reliable. Like most semi-autos over 99% of my stoppages can be traced to magazines. While I've had good luck with KRD, you still have to test every magazine to be sure. If you stick to factory or MecGar, you'll generally have no problems.