Not really rules, but some habits.
1. I oil the hook on my SweetSixteen every time it needs a new bobbin- got into that habit after hearing the terrible sounds it makes if I don’t (yikes!).
2. unplug my iron at end of day even though it is plugged into same surge protector as the lights. So if lights are off, iron is off, but I got into the habit of unplugging iron years ago before surge protectors were a thing.
Rob