Notice that the once ubiquitous phrase "blue screen of death" has just about disappeared from the geek lexicon. XP can claim credit for that.
The point is you can wait too long if your goal is to let others work the bugs out of a new piece of software. After all these years messing with these machines, I avoid the bleeding edge myself. But at a certain point - I can usually sniff out the proper moment through a combination of osmosis and rank spiritualism - I jump in. Otherwise you miss all those cool features and the sick whizbang stuff you can do.
Why? If what you have is working just fine, why upgrade? I've got 2 13-year-old minivans and they work fine and still look fine. Should I upgrade?
I am still using 98SE on this computer and it has about the same number of problems as my XP machine at work. It can run for days turned on without locking up. The XP machines do more strange things than my 98SE. They seem to change settings by themselves and then later put them back the way they were.
That's because XP by default will just reboot rather than display the BSOD. There is a registry setting to turn this behavior off, though I haven't the foggiest idea what it is. The BSODs still occur, (though probably less frequently than in the past (YMMV)), because they are hidden now.