Read somewhere that even some rubbing alcohols have additives, so I always check the label for 99% pure. What do you look for when you buy yours?

God yes. I wrote three whole drafts for a text asking my neighbor if I could borrow a ladder. A ladder. It's a metal thing with steps. My brain kept getting stuck on "hey would you mind if I" vs "any chance I could" like it was some big legal document.

LabCorp, mostly because it's the only one I can ever remember (my memory is not great). Their website is pretty easy to use, which is a low bar I'm happy to clear. I'm a simple person with simple lab needs.

Our warehouse in Toledo has 200 of those generic PIR sensors from 2018. Still running. Like @matthewperry said, low traffic zones are perfect for it. Hallways, storage closets, places people don't linger. You get the same basic coverage for half the price. The money saved on those lets you put the top shelf gear where it actually matters, like main entrances.

Been there, that vanishing act is the worst.