I agree with the others.......don't buy a new warranty. Typically you are going to get 4-6 years out of a computer. By then the technology has changed so much that it isn't worth repairing.
Like you, I buy an extended warranty when I purchase a new computer and that gives me 3-4 years of coverage. After that point, I keep my fingers crossed and when things start going wrong --or it dies, I get a new one.
One thing I did learn the hard way many years ago. Always, always, always have at least one and optimally two backups of your hard drive. I lost everything once and for weeks was weeping with frustration at my stupidity. I teach and all my lessons, grades and research vaporized. I have never made that mistake again!