It's also knowing that some tools don't need to be premium, at all.

The harbor freight parallel claims, for example, are totally adequate. They do everything a parallel clamp needs to do. Yeah, you can get clamps that are undeniably better from other brands, but why do that when you could buy 2-3 times as many HF ones instead? Run a piece of tightly-fitted construction timber up the spin, slather them with paste wax, hammer the nuts so the handle won't come loose, maybe glue a piece of leather or wood to the jaws and it's pretty much as good as anything. To say nothing of mechanically even simpler stuff like a basic spring clamp.

There are also tools that are cheaper to buy from HF than rent for a project. For a DIYer, even if the tool is worse, that's often the better bet since it removes a huge time pressure from your project.