Is it recommended that a person wears glasses all the time?

It depends. Depending on the reason for the glasses, you may be better wearing them full-time. If you are nearsighted (can see close but not far), you may only need glasses for driving. If you are farsighted, you may need the glasses all the time. And if you are a child, you should wear glasses full-time. Special cicumstances, like lazy eye, would be much better with constant glasses wear.
No. Glasses are only really necessary when a patient wants to see more clearly. About the only time when glasses are essential is in children when we're trying to treat strabismus caused by a grossly out of focus eye or accommodative esotropia.