You can shoot really anywhere. I use 23g 1" for quads cause I like it to go deep. You have to be the judge of how much fat you have and whether or not say 5/8" will penetrate deep enough into the muscle. You can shoot glutes, quads, bi's, tri's, delts, traps, calves, chest, lats even. Some places are harder to reach than others and have more nerves which is why some prefer to avoid those areas. Also, you have toi think about if you got an infection, where would you prefer it to be? It's good to try different palces though - some hurt more than others.