I am looking to start a 3-ball arsenal, one of those balls being a spare ball. I have a Columbia 300 White Dot that i just recently purchased for spare duties.

Should I keep my Ebonite Gyro (urethane) which is good for medium oil at best, or buy a new ball to replace that one? This ball is over 13 years old.

I was thinking of getting two new balls, one that works for light to medium oil, and medium to heavy oil.

What should I do?  I shoot for accuracy, I don't have a big hook or do i try to throw the biggest hook possible. I don't throw very fast or very slow somehere in the middle, and i have medium revs.

I am gonna say its more of a swing shot. My ball doesn't swing very wide.

Lets say I am shooting for the 15th board.  When I line my feet up at the set of dots closest to the foul line I am a few boards left of the center dot.

Ok, I hit the 15th board my ball will go to the 11th or 12th board and then hook sharply on the backend.

I am trying to be as accurate in description as possible, but its hard since I am not bowling right now at the moment.