At least on my HTC Hero, 70 apps is the limit. No, I did not run out of internal or SD memory-far from it. But I have been going off trial and error, installing and uninstalling apps. If I go over 70 apps, once I shut off/turn on my phone, it will be completely corrupt, won't give me service, etc. The first time this occurred, I had no idea what was wrong and hard rebooted my phone. Now, if I stay at 70 apps or below, I'm fine. HTC should really tell you this and it is ridiculous considering I have plenty of memory left.