How long do you keep the warranty valid?

[Billfred]

So recently, I came into ownership of a new desktop PC, just for those odd things you can't accomplish on a Mac. I know there's a lot of things that can be done to a standard PC these days, and some of them (second optical drive, more RAM, maybe even a big side window for the fun of it) I'm inclined to add. (Well, I might skip the window.)

That said, I'm also interested in making sure that the hardware I already have works, and that anything that does go on the fritz gets fixed under warranty and not the Money From Billfred's Wallet Plan. I assume that there's folks out there who have been in a similar boat; how long did you hold off before cracking the case open?