I'm a 4.0 player with a pretty fast first serve (lets say 85-100 MPH), usually flat and sometimes sliced. My second serve is always a slice. I can get decent pace and keep it in most of the time. No one picks on my second serve because the ball stays so low. My brother is trying to learn the kick serve for a greater margin for error, but right now his balls are just sitting up, waiting to be clobbered. I play doubles with him every Sunday and I still have to run back to the baseline for his second serve, while he stays up on all of my serves and never gets clobbered. I was even able to mix in a serve and volley on my second serve! My question is, will this hurt me in the long run? Because it sure seems to work well at my level.