I let my five-year-old hold my Xperia and the results were predictable. I've bought a replacement screen, but I didn't watch the install videos first. (Arg! The production music, it burns my cochleae!) Has anyone tried it? How hot did you set the heat gun, or did you use another technique? Should I even do this myself at all? Any advice?

well, it's the same as on any other phone when it comes to the screen itself. On a positive side, back is plastic and internal are easy to remove. But you should get LCD with frame, much easier job in that case.

Hi there. It is not difficult both options. It's easier if you buy the screen with the frame. Once your screen is already broken you just have to remove it and all the glue that sticks to the frame. To glue the new one to the frame there is a glue or a tape with the exact measures for it

Does the back need to come off to unplug the battery before removing the screen?

Yes. It is an easy device to repair and replace parts

I've swapped my screen and the only hard part was removing the battery as the white sticky stuff snapped so I had to resort to prying it up.

Pro tip - don't use a sharp knife to pry a battery as it's easy to stab it resulting in the magic smoke escaping with a bad smell and a melted knife blade (and I'm sure I got lucky )

I got it done, so far, so good. I was able to remove and replace the screen without removing anything but the back cover -- I just loosened the long plastic bracket by taking out the 3 screws near the bottom of the phone. This was enough to undo the old ribbon cable connector and pull it out then feed the new one through and snapping it down. Phew -- I was dreading trying to put everything back where it belonged if I disassembled the whole thing. No thanks to the crappy Phillips screwdriver included with the replacement screen.