15 minuten - 1 uur
I was having early shutdown problems with my ~14 month old iPhone 5 running iOS 7. When I first got the phone, I was impressed that it could get more than 1 day of regular usage without charging. Before my battery swap, I was getting 6-8 hours before needing to charge and it would sometimes randomly shutdown with a 20-30% reported battery level. Now it's back to 24 hours or more, and no more unexpected shutdowns. If you have degraded battery life, I would highly recommend doing this repair.
Installed it myself, took all of about 30 minutes or less with the iFixit tools. Getting the screen open took some persistence. When you make a small gap with the suction cup, push in with the spudger to lever the screen up a bit more and it then you can pry around from there.
The screws are really tiny, so use magnetic screwdrivers and work in a clean environment so you can find a screw in case you drop it. I used the iFixit magnetic mat as well to hold the screws and keep them organized, which made it go more smoothly for me.
It's actually not as difficult as you might think. Go for it!