My 3.5 year old just filled up a smaller (6 boxes) behavior chart I made last week for staying in her bed and not crying at school for two days! She earned a small prize, and I felt overall it went pretty well so I made another one with 25 boxes. She commented that it was a a lot of boxes, but I want her to get into a nice groove with what she was doing before earning something again. I think for her this really works, and I'm hoping she can be successful and fill up all 25 boxes!