Input via digitizer became intermittently erratic. I could scroll screen with finger above screen not touching. Pressing one area made phone act like I had pressed a different area. There was a light streak down screen. This problem was intermittent and would come and go while phone was just sitting around.
Replacing the iPhone 5s screen assembly was pretty easy with iFixit tools and guide. The parts inside the iPhone 5s are amazingly small, said from the perspective of someone who has repaired Powerbook G4, original Airport Express, iPod mini and iPod Classic. It's a wonder of engineering how tiny and precise the parts are, but it makes it a little tricky not to lose the parts if you drop them.
My screen no longer automatically adjusts brightness. I haven't checked to see if reseating the cable connector or transferring over the old ambient light sensor will solve the problem because I don't want to screw up something else. Screen input is good now and that's what matters.
Colors on new screen seem more saturated and pressing seems to require harder input but that could be perception.
Clean a very large area - like the entire table top and the sweep the floor where you're working. This makes it possible to find the parts you drop. When you lose something on the floor, put a flashlight flat on floor with light raking across surface to find tiny parts.
The bonding strap and screw holding it in place on the home button's cable are difficult to keep track of because they're so small and the cable acts like a spring and flings the parts off your table. The assembly is supposed to be captive. Try to keep it that way.
Took one and a half hours.