Question

You should know the location of safety equipment
in the laboratory and
1. use or test it once a month.
2. where it is produced.
3. use or test it once a week.
4. how to use it properly

Answer 1

I would say you should use or test it once a week to ensure it is working properly in an active laboratory since it is a workplace with significant chemical hazards so it would give peace of mind to know on a quite regular basis that it can be relied on in case of an emergency like an eye flush for example.