When registered, all the data will be saved to data cloud, so even you delete the app and reinstall, you can still login and check all the old data. If not registered, all the data will be saved in your phone, you can still see them all, but when you delete and reinstall the app, all data will be gone.
Lunar the watch, could save 7 days data in itself and it can sync to your account once registered. Data in your phone can't sync automatically when registered, for now.
That's to say, for example, if you login every 7 days, all your data will be synced and saved in data cloud; if you registered every 10 days, the first 3 days won't be saved, only the last 7 days.
So, if you don't feel like registering everyday but still want to save all the data, we would suggest that you ould register every 7 days.
How to login?
1. click the plus sign "+" .
2. choose one way to login: Facebook, Wechat, Email, or use your email to create a LunaR account.