I just started keeping one two weeks ago. I'm not all that thrilled with the one I'm using, but already like having one. I agree with you Captinbipolar on the fact it's telling me what I already know, but for me it's good to see how drastic the change is in comparison with sleep/meds missed. I know my sleeping is all over the map- but seeing it is shocking?! I've already used it to help get better sleep and have an easier time waking.