10 - 30 dakika
My mom has my hand me down iPhone that was already having problems with battery life. It go to the point where she could only use it for about 10 minutes then have to put it on the charger. So it was about time I came to my senses and remembered I could change it for her myself.
It was very easy and very fast.
Don't lose the little copper part that pops off and grab a set of tweezers.