For me it's strictly based on "does this thing make me want to scream like an old horror movie victim"
smol spiders i don't give a shit about unless it looks like a tick in which case NOPE. For larger spiders it depends entirely on what kind it is, stuff like orb weavers get a polite relocation to my balcony where they can hopefully set up shop to catch yucky flies and we can proceed to merrily ignore each other, jumping spiders get an actively friendly relocation to the balcony mostly so i don't accidentally squish them, and basically anything else gets the boot and tissue.

Orb weavers really are the platonic ideal spider, you can literally just put two sticks on a plate and they'll make a web there, then as long as you feed them they just keep sitting there indefinitely.