I had a problem with TimeMachine, which intermittently stopped working, with no alert, leaving me with no recent backup when I needed it. Trashing prefs didn't help and even discovering where Time Machine logs are kept in Sierra is now complex. Time Machine Editor, which I've used in the past, didn't overcome the problem.
I downloaded the free demo of iScheduleTimeMachine from the dev's web site. Works fine on Sierra, so far completely reliably. Bought it once the trial period expired (though the demo was still working) and I'm happy.
The ability to schedule backups at a set time of day etc is also a useful plus..