Those are great another option which i like is the kind without the battery in them you give up the ability to see the rpms but they dont need a battery to stay going.
I have one exactly like this on my machine. been on since day one. Wire tail from the timer wraps around one of the plug leads and is cable tiled on screw the timer up where ever you can and your good to go. 10 minutes to fit easy as.
I change my oil and filter by the hour meter at every 100 run hours.