20 - 30 Minuten
Battery could not last the day on standby and turning off at ~20%. Battery draining tasks like GPS and games would turn off the phone on its on.
Everything works after taking it apart and putting it back together.
The new battery lasts much longer; but not as good as the original I don't think. It's hard to compare though because the new original battery was running different iOS and things.
The guide was very helpful although I had to watch a more thorough youtube video for the technique of detaching ribbons and stuff.
Fairly easy job. Way more economical compared with what repair places/Apple charges.