how well will these stand the test of time?
PLA is common, really easy to print, vaguely biodegradable, and strong — but it is brittle, will deform under load, and will degrade in UV light.
PETG, roughly the plastic in soda bottles, is a good choice for functional prints and addresses all the problems with PLA but is slightly less strong and is more difficult to print fine detail with.
ABS/ASA will produce prints with strength and durability truly like commercial products, but you need a pretty decent printer + enclosure to avoid warping. Also it produces toxic fumes while printing.
Tradeoffs.
But costs twice as much as PLA, and absolutely requires an enclosure to print.
Tradeoffs indeed.
Yep. You don't get out of it without learning some materials science...