Is it not a good idea to nap mid-day?

I am almost 40 (not sure if that has anything to do with anything!) and, lately, I have been wanting to nap during the day. I tutor in the evenings and do school work during the day. Three o’clock in the p.m., I’m ready to watch the back of my eyelids. I usually fight it off, though.

What are the pros and cons of napping during the day?