That's the beauty of Macs in my opinion. I can't speak for the really really old models, but all the metal MacBook Pro's as a general rule (at least in my group of friends, family, and co-workers) those things last and last. My parents are rocking my old 2008 MacBook Pro 13 – and with the SSD I put in there it's still extremely zippy for the web browsing they mainly do on it. I've had yet to own a PC laptop (owned most of the big name brands) which lasted longer than 4 years without every single thing on it being fucked up in some small way - like the keyboard, screen, ports, plastic case, etc. (and I take care of my eleowned ctronics and are gentle on them).
My 2009 Mac Pro is a friggin beast still. My 2012 Mac Mini (2.3 i7 quad-core) has been raped left by creative suite and still kicks it perfectly. I've even built my buddies YouTube channel intro video in After Effects and Premier Pro on my little 2014 MacBook Air 11" - even though it has something like a stupidly slow 1.4GHz dual-core i5 in it and only 4GB of RAM it chugged through having Adobe Premier, After Effect, InDesign, Illustrator, and Photoshop open at the same time multitasking.