Question

when do you need to wear a hard hat?
only when the company rules say you must
whenever there is an overhead hazard or whenever company policy says you must
you must always wear a hard hat on any kind of construction site
it is your choice when to wear a hard hat. no one can tell you what to do

Explanation:

Hard hats are safety gear. They protect from overhead hazards like falling objects. Company policies also enforce their use in certain areas. So, wearing is based on both hazard presence and company rules.

Answer:

Whenever there is an overhead hazard OR whenever company policy says you must.