I don't keep track, but I wouldn't be surprised to find I averaged 2 balls a round, with one ball being my average for a good round and those occasional really bad rounds where I might lose or OB 4 or 5 balls. Its expensive to have a big hook! I think I've bought 3 dozen so far this year, I will probably need one more.
A few years ago I managed to play something like 6 straight rounds with the same ball, but I was playing to 4 then. Now I'm more like a 7 due to lingering injury and general crappy play, and I think I've probably only finished a couple rounds this year (out of maybe 20-25 total rounds so far) with the same ball I started. Guess its pretty obvious where those strokes are going!
Bruce Katona -- how do you lose 1-2 balls a round (unless "use" isn't the same as "lose" for you) and still maintain a +2? Or are the rounds that count in your handicap the ones where you never lose a ball, and the ones where you lose them all the ones that don't count? If only it were the case with me....I still remember a few years ago shooting a 78 with 10 penalty strokes. Its bad enough taking 10 penalty strokes, but its really bad when you still have to count the score in your handicap!!