5 - 30 Minuten
After using my PS3 for many years (original PS3 around first launch) I guess the YLOD or an older consumer electronics product caught up and wouldn't boot up.
Oh and after much use with my iphone4 I needed a new battery.
Iphone battery change was very simple. Cheers to apple for a service friendly design on the 4th gen and to ifixit for easy to follow instructions.
YLOD took much longer than 1 hr. Perhaps it was due to me making time for my crazy 2 year old and my pregnant wife in between.
I had several problems with the YLOD repair. Pics of the product in the repair guide are only for the wifi version and the much older PS3 I have (no wifi, no mem card slot) had some different details to tend to in that area. Also the provided thermal transfer material liners were a beast to get off. Perhaps par for the course but that gave me lots of trouble.
In the end though my PS3 works again and I am very happy.
Don't give up on your system before you try to repair. Even if it doesn't work you get a nice little screw toolset and a heat gun.