I try very hard not to use rewards for my children, but there have been a few times that I have found them very useful. My children love stickers, and I keep them as a rare treat - mainly so that they keep their power. I have used sticker charts 4 times in the past, and am using a new one the last day or two. Because they have not been used often, and stickers are used rarely, they are very motivating for my kids.
I used a sticker chart for potty training for both Delta and Echo. Last year, when I was expecting Foxtrot, and knew that we would need to move Delta into the back of the mini-van, we used a sticker chart for doing up his carseat. (Delta doesn't weigh very much, so is still in a 5 point harness car seat.) Delta has also had one for practicing the violin for a while.
Well, now we are training Echo to do her carseat up by herself. She had succesfully done it a handfull of times, but wouldn't make the effort. (It was also a lot harder earlier with winter coats....) Well, yesterday I setup a stickerchart, and she has done herself up everytime since (earning 8 stickers so far) - and I have moved her carseat to the back.
In a week or so, I will print up a certificate for her that she can do up her carseat - and that will be it!
Gotta love the power of a sticker!