If balls only lasted 300 games then we'd all be broke with a closet full of old bowling balls. As long as you regularly maintenance the ball and take good care of it then it will last as long as you want it... until it cracks in half and then you cry.
But obviously the ball start to lose its hook capabilities and reaction even if you take care of it right? I'm not saying that I want to throw my ball away, I still want to use it because it is such a versatile ball, but I noticed a decrease on its reaction lately, regardless if is the first or the thrid game on my league.
Remember "lose its reaction" is a relative term, not an absolute one.
Balls lose a small portion of their reaction, WHEN you take care of them: clean them, do oil extractions and do refreshing of the surface AND re-surfacing, when these are appropriate.
Sometimes, depending on the ball and it's coverstock, your rev rate, the surface you're bowling upon and several other factors, the time increments required can be a lot smaller than you might think.
In addition, being cheap won't help you.
- Do the service when it's required NOT when you fell like or you have the extra $10 or so laying idle in hour pocket.
- Know when you have gotten the maximum service from your ball.
- Recognize when you or the conditions have changed and it's not the ball's fault.
- Buy a backup IF you really love that ball but also realize that 5 or 10 years down the road that ball might not perform the same way as the prevailing conditions allowed it to 10 years ago.
- Buy a new ball when you have to or when you need to.
- Remember you "buy a ball reaction; you don't buy a ball."
