If I find a good deal on a ball that I know can/will be used in the future by me or my son, I'll get it. Either close-out or an auction that stays very low. Even if future plans change, it still becomes ammunition to sell for maybe a few bucks profit or trade for something else. Or some times it's something that may be limited or rare. On a couple occasions, I may have won a ball in a raffle (I've won three this way in the current PJBT tournament season). It's just something that allows me to geek out.
I just gave two away as prizes to my travel league teams (I was the coach this year). I had offered a ball as a prize to the individual who finished the season with the highest winning percentage. It was a Peterson (Pederson?) format league. Since the top two came very close and it was a real battle, I added a second one from the rack for the second place kid. Fortera Exile for the winner (I won it in raffle), Burgundy Ringer for second (picked it up very cheap as a future replacement possibility, but have changed plans).
As it stands, I now only have four NIB balls. Motiv Covert Revolt (future use for either son or me); Motiv Forza Redline (probably me); Hammer Deep Purple Taboo (0.060 diff...HOW CAN THAT BE??? I have been using hammer the last year and picked this up, but I think I will be slowly moving to Motiv going in to next season); and Brunswick LT48 Pearl (BVL edition from Johnny Petraglia PBA50 event; no plans for this ball other than holding).