Low battery warnings. Got about 2000 miles out of it, which is Ok I guess.
That makes it... what, on the order of 1.5 cents per mile? Not too bad. Worth it to me for the features, but then having it die and needing to go get a new one is a pain. On the other hand, that's almost seven pairs of shoes if you replace at 300 miles....
My thoughts for your leg injury... I know exactly what you mean. I have one very weak ankle and I have the same constant risk....