We put the fear of the burn into our DS at an early age. We go to a condo on the beach 1-2 weeks every summer. Every time we see a burned body we point it out, tell him how painful it is, and tell him how to avoid it. He eagerly wears a full sun suit (long pants, long sleeve shirt, hat at Solumbra
http://www.sunprecautions.com/)
It's expensive and as he grows we have to size up so it's comfortable, but it's so much better than creams an lotions, which are toxic and have to be reapplied to be effective.
Yes we look like freaks on the beach but we have never suffered painful burns and we stay out all week long.