In that case though the data collection is presumably required (to some extent) for the app to function. If you're tracking a users periods then you presumably

In that case though the data collection is presumably required (to some extent) for the app to function. If you're tracking a users periods then you presumably need to store data about their period. It's probably a case for why we should have anonymous users accounts for those kind of services. I don't know how practical that is.