Bluetooth lock is very reliable with my iPhone, but not so much with my wife's fob. Her fob fails often enough that I sometimes just wait and watch to see if the Bluetooth lock is going to open for her. On several occasions, I have "opened and closed" her fob's plastic cover to keep the electronics working. Nothing else was done to it.

To be fair to Kwikset, they replaced her fob once under warranty without charge.