Just got back from being at the pro shop for de-oiling my Roto Grip. Part of the conversation entailed the fact that if you de-oil every 50-75 games then the 4th time the ball needs de-oiling you should consider replacement, or the next time for sure.Interesting fact that Mike was sharing with me, is that the oil is absorbed into the cover stock and because the covers are so thin, the oil then begins to seep into the inner portion. So, if you cut a used ball in half, then you would see the oil seepage look like ant tracks. Once you de-oil the ball, then the ant track is just a void. After so many de-oils, and so many voids, the ball won't react the same.