Easy, but having an OtterBox case in the first place would have been easier.
5 - 20 minuten
My 13yo niece dropped it and the display no longer worked at all (chunks of glass missing from the corner). When powered on, it would buzz twice, pause, buzz twice, pause, continuously. She took it to the Apple store, where the certified Genius told her the phone also had water damage and couldn't be repaired. Genius was wrong--my daughter happened to have a working 5c, so I swapped the working display with the broken one to test it, and with the other screen, it worked fine.
I had previously bought the iPhone 5 Cellular Signal Antenna Flex Cable Replacement Part with Tools Kit - FIXSTOP (http://www.amazon.com/gp/product/B00S5IO...) for a different repair. This kit has all the right pieces for this repair, and was only 10 bucks.
Disassembly is simple, reassembly is slightly harder because the screws are so small. The replacement screen's pin harnesses were harder to line up than the original's, but I eventually got it. Make sure there is no debris between the pin harness and connection--I almost broke mine trying to push down when there was something there.
Once the screen was on and put back together, the display didn't work properly--there were large blocks of pixels that didn't look right, and the touch screen didn't work. I had to detach and reattach a couple of times before it worked right.
All in all, it was worth the hassle.
If you have a choice between buying a replacement glass without home button or camera, or buying a full replacement screen with home button and camera, and you're not sure which one, buy the full replacement. Swapping the button and camera from the old display is probably not worth the 10 bucks you save.
Make sure you have the right tools (see above for the tools I got).
Make sure you have a space where the microscopic screws won't get easily lost (a small magnet helps).
Using the right amount of force to push the display connectors back on without breaking them is a bit of an art.
It may take a couple of disconnect/reconnect/reboot before the display