I'm a decent 4.0 / 4.5 recreational player who never really worked on his volleys. So this winter I decided to get a ball machine and practice my volleys (starting almost from scratch). For the past four months, I've been training twice a week with my machine (which is great for practicing volleys), and also had a coach helping me with technique once a week. I must say I made great progress in four months. My volleys are solid on both wings and my muscle memory seem to have done the job, since I dont't have to think about anything when I'm hitting, and yet I hit with good technique (according to my coach). My question is: should I keep practicing twice a week with the machine, or is my muscle memory already built in, so that I only need to hit volleys once a week with the machine or coach (plus at least one match or friendly hitting session a week) to make sure I don't «lose» what I just learned?