5 - 20 minutes
Cracked screen from an eBay purchase. I've handled a lot of these phones personally but being able to repair and see how these phones were constructed was a great experience.
After following the instructions online with also the help of a friendly Youtuber, the whole process went quite smoothly. I'll be honest though I was super nervous. I tried to take as much care on each step to ensure I didn't break either the phone or the part. To my surprise though, with jabbing and pushing both the phone and the new screen held up quite well. I was also surprised how easily the screws came off and how the screen just snapped into place. "Good as new" I exclaimed as I turned in the last screw. However after turning it on I realised the front facing camera wasn't working! Dreading having to contact iFixit for another part, I opened the phone once again to see if the ribbon cable had been secured properly. This time opening the phone was done super fast unlike the careful first time. Now with the screen exposed once again I properly snapped in all the ribbon cables, closed it up and hey presto the screen and the camera were as good as new.
I really surprised myself and if you're phone is out of warranty and you're feeling daring I'd definitely recommend doing it!
Be patient and be prepared to start again.
Make sure you have plenty of work space and don't be afraid to be bit rough sometimes... but not too rough ;)