When to stop rewards/stickers?

fiasco

Stupid me, I set up a system where he gets 1 sticker for pee, two for poop, and after 10, we walk across to the toy shop for something little.  We just started Friday, he earned 10 stickers just from peeing (he poops at nap time in his diaper so far) & he got his first toy tonight before bed.  He was psyched enough to get the animal stickers on his chart, I should have left it at that, but now I fear I've set a precedent.  When do I stop all this reward/incentive nonsense?  Maybe it will just fade away? I'm assuming sometime before college!

JCM

For DD we have a sticker chart & she gets 1 sticker for pee & 2 for poop but she's only pooped in her potty once & the rest before getting out of her crib in the morning or naps too. Our sticker chart has 126 spots & that is the only reward she gets, well the sticker & a potty song & dance, as well.  We are nearing the end of that sticker chart but I think I will get another one because she really loves the stickers.  Maybe you could change charts or tell him that since he's earned 10 & 1 toy for peeing in order to get another toy he needs only gets stickers that add up to a toy for poop?  Maybe have a different chart for poop?