I only buy a couple dozen at a time, and never have more than 2-3 dozen stockpiled. I've made the same mistake as @Iceman! in the past, don't want to do it again. I'm not a total ball ho, but I do switch it up from time to time, and don't want to be stuck with a big stock of balls I'm not going to use. If it's just a couple/few dozen, I'll sneak them into my bag 3 or 4 at a time as "water balls" and use them on risky holes to get rid of them.Love the donation idea, especially to the First Tee or High Schools.
Other thing i learned here is that having a stock pile fo 2-4 dozen probably isn't enough. I better load up.