I don't know about the 5, but I've used my Intuos 4 for two years and never felt the need to replace a tip. On my original Intuos, which I used for about ten years, I replaced a tip once, more on general principles than anything else. And I didn't notice any difference afterwards. I'd say don't worry about it.
Hey guys. I picked up the Intuos 5 about two weeks ago and just started playing with it. I read that the nibs can wear out pretty quickly and I was wondering if you guys would recommend putting a screen protector on the screen and if so which one?