We're on year 5 with our HP Core i5 laptop. Still runs pretty well, although the fan could maybe use a deeper cleaning than just compressed air. It's also been a while since defragging. virus/ad/malware scans are fairly regular, also. Then again, this is our home PC used mostly to stream movies, play a few games, web browsing, and bills/taxes. Nothing intensive.

My work laptop is replaced more frequently. Since 2007, I've had a Dell Latitude D410 (2 years), D430 (2 years), 2 different Lenovo T420 (2 years, 6 months), and a T440 (got a month ago).