Always wear knee and elbow pads, to save wear and tear. also got shot in the gands a few years back, and never go out without slide shorts and a cup.
As for bounce vests - unless it's very hot, I always have one - for woods and walkons, it means I don't worry about playing up close and agressive, and in tournaments, as I used to play snake, it takes the sting out of the occassional bunkering..
As an extra top tip - I've started wearing a walkers wicking base layer under the vest - keeps you cool and dry in hot weather and warm in the cold. Well impressed with it so far.