If you're a scuba diver you'd never dive without a buddy. Some say that's because, if you meet a hungry shark, there's a 50-50 chance he'll choose your buddy from the menu. There are other good reasons for flying with the companionship of another pilot; if not all the time, at least occasionally. This is different from recurrent training with an instructor-another good idea. But flying with a non-instructor pilot takes on a different dimension with its own unique benefits.