Torres.blair nailed it, moisture ruins everything.

Work just fine" is a pretty low bar. You might not get complaints, but you're not getting the best results either. Good shears make cleaner cuts that keep hair healthier between appointments. It's not about the client noticing, it's about the actual quality of your work. Saving a few bucks now costs you in the long run with faster dulling and worse performance.

Avoid natural lubes near bearings, they wash out grease fast.

Only if you want your holiday fire to smell like old cardboard and regret. Creosote is nasty, sticky stuff that can actually catch fire in your chimney. In my experience, mixing that with stored junk is how you get a very exciting, and very expensive, fire department visit.

You just made me check my own field notes.