Its absolutely unbelievable how well those older MacBooks hold up. I am writing this on my trusty 2010 17' MBP. I have many great memories and this laptop guided me through thick and thin over 14 years now. Its truly stunning what the internet can do IF you are willing to learn and spent the time to postpone purchases.
I still have me trusty ole BMW e39 from 1996. Thanks to YouTube, I did learn any and every maintenance task possible on this car, so it runs super nice. It really pays off to build up know-how over time. Same with Apple devices. Don't underestimate yourself what you can do, and Unlearn what "they" have programmed you. Truth is, most older devices have been a lot better designed when it comes to longevity and durability. Todays tech is junk most of the time and doesn't last half of it. Look at it this way, One care less purchased over your live saves 25K, one less Mac saves 2,5K. Its that simple. When I travel to South America and other 3. World countries, I really got it down how they trick the system. A big part is to use many products a LOT longer and repair the hell out of it. That's what we in the West will have to learn, especially when our currency are going in the crapper.