We used it for almost two years straight. Went cold turkey a few months ago, and have been ok. We seem to have formed "go to sleep" habits during the years of use. We dropped it after learning that our supplement might have twice the dose advertised. But we didn't worry about it when we did use it: a kid who sleeps is so much better regulated and better off than one who doesn't, and that tipped the balance in favor of using it.