We just went back to one. For a number of years we let a phone do this job.

Then on one super rough day, both my wife and I were just drained! We hit the bed and were gone, snoozing hard.

Well, neither of us managed to have a phone charged well enough to wake us up and so we just didn't! Kid late for school, late for work, late, late... total pig of a day.

I picked up a $10 clock almost exactly the same as our old one, which did not survive our last move.

Now it has a fresh 9V battery and is set a bit behind the phones. It is the backup.

And we both kind of like having it again. We get a time display at a glance and it does wake us up nicely without being brutal.

These things are simple tech, but useful, low hassle tech too.