You don't have to sign in every time you log on. You will be asked for your PIN or biometrics whenever you login and access sensitive data or execute a transaction.
In the event you lose your phone or are changing your phone, please make sure you already have your recovery phrase (without this you will lose access to your account and you should already have a copy of this stored in a secure location) and back up your Vault. Install ShareRing Pro on your new phone and use your recovery phrase to login to the ShareRing Pro app and then restore your Vault from a backup, after your Vault has been restored successfully you can remove your account and back up from the old phone.