I don't put make-up most of the time. But on formal occasions where you have to dress up, putting on make-up will be necessary (just don't go for the opera look please XD). It shows that you have the effort to be presentable where everyone is. Dressing for occasions, same goes for make-up. It's not absolutely necessary, but for some events where you are required to look presentable, make-up is needed ^__^