A series of Apple PowerBooks over the past nearly 15 years have needed service twice:

Once for a new screen when I dropped the thing four feet onto a marble floor. The rest of it continued to work fine.

Once (a different computer) for a new internal modem when I inadvertently connected it to a digital phone line.

Other than that, no problems yet. I know Apple isn't perfect, everyone makes a lemon once in a while, and I'm not trying to ignite yet another Macintosh-versus-Windows religious debate, but based on my experience thus far (and on confirming evidence such as the recent Consumer Reports survey that puts their reliability as the industry best) I save my money when it comes to extended warranties.