Depending on how you use Clever Dialer, your blocklist can become quite extensive and quite valuable for you over time. You surely do not want to lose this data when you buy a new phone. Clever Dialer supports Google Backup to solve this problem.
The following data will be saved via Google Backup and you can restore it if you buy a new phone or reset your current one:
Blocklist
Exceptions
Settings
You can find more about Google Backup here.