Upsides and downsides of hiring a summer helper?

I am thinking about hiring someone to help me in the busy season and the idea of a high school kid as a summer job sounds like a promising idea. I wouldn't have to pay them a crazy salary, they are like sponges with information and they are typically more physically full of energy. I wouldn't be able to send them on their own, but they could help me get a few more jobs done in a day.

I am wondering if anyone has tried this and what would be the pros and cons of doing it?