It is just a personal preference for me. I feel that I can get away with a mis-hit easier on on dry turf than I can on wet turf. The wet turf just compunds the problem(s) associated with a mis-hit. I am speaking about a sclaffed (fat) shot here. The wet turf (mud) just makes things worse. If you have ever played a ball out of real damp, thin lie you know what I am speaking of. In reality, I don't normally ground my club at any time, as I would rather be a little bit thin, than to take a chance of being a little bit fat. Like they say "thin to win". GJS