Sticker charts are the most tried and most abandoned tool in this whole subject. Both halves of that are worth taking seriously: they work at first for a real reason, and they stop for a different real reason.
Why the first two weeks go well
A sticker is immediate, physical, and it accumulates where a child can see it. That combination is genuinely powerful and is the same thing that makes a loyalty card work on an adult. Nothing about it is a trick.
Why the fourth week does not
Three things run out, and they run out in this order.
| Week | What is happening |
|---|---|
| 1 to 2 | The sticker itself is the reward. Novelty is doing the work |
| 3 | Novelty is gone. The chart now needs something at the end of it to point at |
| 4 and after | If the only things on it are easy, there is nothing left to earn by trying |
So a sticker chart that dies in week four usually died of having nothing on it that was hard, and nothing at the end worth crossing a room for. Adding a far-off prize and two genuinely difficult lines will often restart the same paper chart you were about to throw away.
The one that is not fixable
If the chart takes stickers off, no amount of prizes will save it. A child who can lose the thing they earned will protect it, and protecting a total means attempting less. That is the one design decision worth being strict about.