I installed a Leviton Decora Style timer with 10 20 30 60 pushbuttons
in the bathroom. A small LED flashes just before the fan shuts off.
As I recall, it was just two wires and was a direct replacement for
the switch.

I was thinking of installing one of those timers for an exterior light.
Would like to turn it off as I head out the door and have it shut off a few
minutes later.

However, I haven't been able to tell if that timer has a manual override
that lets you turn the switch on full time till you turn it off?

Anthony