Touch ID Improvements
For the first six weeks or so, my experience was that Touch ID worked pretty well for a day or two, and then the accuracy rapidly declined. After a few days, it would more often than not fail on the first attempt. Several times per day, it would fail five times in a row, so that I would have to type my passcode.
I tried cleaning the Touch ID sensor. I tried retraining it many times, using different fingers, different parts of the fingers, multiple copies of the same finger, etc. Nothing seemed to help.
Because you can’t have a passcode delay when using Touch ID, this made Touch ID much more trouble than it was worth, so I turned it off for several weeks. The iPhone was immediately more pleasant to use.
A couple weeks after updating to iOS 7.0.4, I decided to give Touch ID another try. I trained it with four versions of my right thumb. I had tried this before, but this time it worked. Over the last nine days, I have unlocked my phone probably at least 200 times, and Touch ID only failed twice. The two times were consecutive. I had just entered a building after being outside without gloves, and so my fingers were cold; I’m not sure whether that has anything to do with it.
I’m not sure whether the improvement is due iOS 7.0.4 or happening on a more effective training. In any case, 99% accuracy makes a world of difference. Before, I had dreaded unlocking my phone because I expected it to fail, and fail, and fail. Now I just assume that it will work. And it’s worked through dry skin, sweaty hands, slightly dirty hands, lotioned hands, etc. It even worked, sideways, when my phone was in a car mount, and swiping and typing the passcode would have been awkward.