I apply something like this to most of my purchases. If I am buying a new phone or some computer hardware, I want to be able to fit another replacement for what I'm about to buy into whatever my budget is. The same goes for clothes, tools for the garden like a tiller or a chainsaw or whatever.
And you know what? It's a decent approach: I have a used Ryzen 5 1600 in my computer now (upgraded from Ryzen 3 1200), as well as an RX 570 (and a spare RX 580 for similar price, bought recently as new old stock), because under that reasoning that's all I can afford, yet it's all that I realistically need. Some spare HDDs (those die more than most other hardware) and a mobo and everything in the shelf next to it. If any one of those parts die like they have in the past, I don't have to cry about how expensive replacing everything will be, nor wait for shipping, just spend 30 minutes swapping out parts.
As for longevity of various items: I don't quite buy it. Sure, there are also people with Stihl chainsaws that have lasted them decades, but why would I spend 5-10x more money, when I can get a new Chinese chainsaw for about 100 EUR that will be enough for all of my casual usage needs around the farm? And once it inevitably stops being useful, I can get a completely new one without a worn engine, while still having some spare parts for repairs. I can think of very few items where I'd want the latest or greatest, even my daily driver phone isn't top of the line and only stands out because of IP 68 and being shock proof (up to a degree, dropped it out of my pocket and on concrete while doing pull ups, didn't even crack the screen).
Perhaps the only exception to this is something like services: dental care and other healthcare procedures, no reason to go cheap on either of those, but then again, I live in Europe so that's not a very contested subject for me due to the overall affordability. Still pondering these thoughts in regards to food, but store brand food is generally both affordable and reasonably healthy over here.