After using this app for a year, it somehow glitched all the info I'd input, will not allow me to easily restore the information and repeatedly deleted when I tried to add past periods based on screenshots I'd thankfully taken when it started acting funny. Wish I'd kept a calendar with pen and paper instead. The app is fantastic if you'd like to reconstruct your entire year or more of tracking for a doctor's appointment and find you can't trust the app to do so.