I kind of agree with Amateur. For a while I was bringing two balls - mild and full hooking action. That way I could choose which to use after the practice frames. Beyond that is overkill. Now I'm down to one ball -
Brunswick Monster - for the next 6 months. You can definitely make one ball work on any THS lane condition.
I have 8 balls at home because I bought them all used, and had no clue as to what each one would do.
I find it fun to own more, but if you find it a burden, as your signature implies, then just be very sure that the two balls you own (plus a spare ball) are the ones you feel most comfortable with.