If you don't test your restores, you don't actually have a backup. You have to test the config first to make sure it works for how your system is setup. An all defaults system should work out of the box, but if you start to alter and customize your system in ways that the backup is not configured to handle, you are in deep risk.
i hate tinkering so i would never do anything that disturbs the system itself, timeahift advertises itself as a backup system, never seen anywhere that said backup needs to be tested, whatever that even means. besides i shouldn't have to do that to begin with.