Many years ago I read the Kyle David Miller story and pledged to keep my son in a 5 pt harness as long as possible. I know a lot of parents move to a booster at age 4, but my son will be 6 in a few months. We haven't switched yet. Are there any other moms who are holding off? I will probably go to a booster when he is 7. The Foundation for this boy, suggests age 7-8 as long as they fit. What age did you choose to switch and why? Thanks.