I think it is when there is no more room in our bag and you set it aside. When you don't pick it up for a while and don't miss it, then it is probably time. I recently went to go to a Storm/Roto demo day. I tried 4 balls from different angles, 5-10-15-20 boards, to see which ones worked for me. I already have a Code black, but it is a different drill from mine. Code black with a different drill was smoother off the break point. Dare Devil and Wreck-em both started up too soon. Couldn't get them down the lane to where I needed them. Had the same issue with the Wrecker when I owned one. Street Fight got down the lane without any problem and had enough energy to carry from the outside. No Rules Pearl was the only ball that got down the lane for me and was still recover from all four angles that I tried. The balls that started up early would only work for me from 3rd and 4th arrow. Street fight couldn't recover from 3rd or 4th arrow. If I do buy a new ball for shorter or lighter oil, it will be the Street fight. For an all around ball, it will be the No Rules. Sorry this turned out to be my review of the balls. What I am saying is, a ball you are giving up on now may be a great ball in a different house or tournament. De-oil and resurface the balls you are not using, put it on the shelf and take it with you if you have to bowl in a tournament at a different house. Many bowlers have pulled an old ball out the the closet and bowled great with them. Could be you are trying to do something with them that they are not designed to do.