Back when reactives first hit the market, I got an AMF Ninja, after a couple of months I noticed that it just didn't have the same reaction. I mean it was a very noticable change in performance. One day my sales rep for AMF stopped in and I told him about my Ninja, he flat out told me without batting an eyelash that these balls were good for approximately 100 games and that you would see a marked change in performance around that point. I was stunned that he so openly told me this, knowing how much these balls cost at the time. Whether or not this is planned obselesence by the manufacturer or just the nature of the balls themselves is hard to determine, I'm sure the ball companies want to sell balls, but its discouraging to know that these balls don't have a long life at their optimum performance levels. I'm certain when you buy a set of golf clubs, skis, tennis rackets and other sports equipment you expect to get more than just 1 seasons use out of them.
Of course any bowling ball can last a lifetime if you don't care about performance, but if you do then be prepared to open your wallet on a regular basis.