bluenotebob
Guru
One thing you might consider @sevenfourate is to fit a simple odometer on to the bike. I have one on each of my bikes - and I swap my Garmin equivalent onto whatever bike I'm riding.
That way, if one fails, the other keeps going and (in theory anyway) you shouldn't have the problem you've just experienced.
That way, if one fails, the other keeps going and (in theory anyway) you shouldn't have the problem you've just experienced.