With that I think a lot of it is knowing what's near impossible to mess up so you might as well buy the cheapest crap you can find, and what matters so much you

With that I think a lot of it is knowing what's near impossible to mess up so you might as well buy the cheapest crap you can find, and what matters so much you should just pay for the big brands even if you have to make everything else crappier to afford it. It's all the same lottery of counterfeit chips, some product categories they have it figured out, some they don't. And a lot of the time, you can just design in such a way that it doesn't matter if the parts are quality. Like, yeah, if you make a lot, you will see a few failures in power conversion or handling parts. So use a USB supply they can swap. One or two switches are going to break most likely. So don't use a mechanical lid switch that's constantly held down, unless you make it swappable. Your 3D printed part might have varying quality, so design in such a way that it still works on a badly tuned printer. There's always that one part that you don't know which one to get and none look very good, but I see a lot of commercial products with lots of unnecessary unique niche parts that could have been a common standard thing.