Low bounce (0-10°) is ideal for shots from tighter lies and firmer turf conditions. Generally with a narrow sole width, the leading edge of the blade is closer to the ground making for cleaner contact from this lie. Using a low bounce wedge from heavy rough or soft bunkers increases the probability of hitting the shot "fat" resulting in a shorter distance traveled with low amounts of spin.
Medium bounce or standard bounce (10-16°), as determined by the club manufacturers, are the best for all around use. Wedges with this bounce option are usually more versatile for use in a variety of lies and are easier open the club face for high lob or "flop" shots.
High bounce wedges (16-18°) are best for use out of soft surfaces (heavier rough and sand). The combination of a wider flange and a lower trailing edge prevent the club from digging to create a smoother gliding response along the ground. Using a high bounce wedge from a tighter lie brings a higher probability of "thinning" the shot resulting in a very low launching shot with uncontrollable distance.