Chances are you're going to connect on a personal level with the people you're working with. Plus, since you care about the task you're performing, you'll want to stay up to date on the work even after your vacation is over. Make sure the organization you're working for is willing to send you updates after you've left [source: Schaler].
If you're working with children at a school, you might want to keep in touch with them as they get older. But even if you spend your time building houses or cleaning up trails, you'll probably want to see how the work has progressed over the years. If an organization is willing to update you, that's usually a good sign that, at the very least, it's committed to staying involved with its volunteers.