Not just test the backup, but practice and ensure you are familar with the recovery process as well. Having a clear plan of what you will do if that disk fails/

Not just test the backup, but practice and ensure you are familar with the recovery process as well. Having a clear plan of what you will do if that disk fails/machine is lost/etc. is better than troubleshooting and fumbling with tools while the clock is ticking. A written procedure may be helpful as well (I have one for my Proxmox server for setting up the machine and restoring the VMs from the backup disk).