If the pivot balls are loose in the arms, then its time to replace the arms. I have never had that happen to me. A hard crash could enlarge the hole and make this happen though. With the clutch, your thrust bearing should be cleaned and regreased every race day. The spring shouldn't need to be replaced unless you are having problems with clutch engagement. Same with the clutch shoe. This is the part that actually contacts the clutch bell. The other parts inside are the clutch weights and dont usually wear.
Some really serious racers replace the thrust bearings every race and have a set schedule for clutch shoe replacement. This type of maintenance is required more on high traction tracks with high powered engines along with 20 min or longer mains. What is it like at your races?