Do I need to have sign-up for a QualityTime account before I can use the app?
You are not required to sign-up before using the QualityTime app. You can use the app without a QualityTime account. You will be able to see the detailed usage up to last 14 days and the data is only stored locally without Cloud back-up.
If you create a QualityTime account, you will be able to see detailed device usage up to the last 6 months, and the usage information will be securely backed-up in the Cloud so you won't lose it.