20 - 40 minutes
Earpiece speaker on my iPhone 5 started failing and 90% of the time I couldn't hear anything from whoever I was speaking with unless using the loud speaker.
I ordered a replacement earpiece speaker from iFixit and as far as tools go, I already had the iFixit toolkit, which is a gadget repair savior. Everything was explained in excellent detail on the website. This was my first time opening my iPhone by myself and performing a repair. Couldn't have gone any better.
1) Be careful when pulling up the screen. Some people underestimate the importance of pulling up on the screen carefully. It could come up faster than expected and next thing you know, you've ripped the cables at the top of the iPhone that connect the camera, etc..
2) Use a small plastic painters platter to set down your screws. Reason I say use this is because it has several indents and you can use each one for different size screws so you don't get them mixed up.