5 - 30 Minuten
My wife's iPhone 4 took it upon itself to leap into a "bowl of water" ! We dried it out with hair dryer (at a distance) plus white rice for 2 days. But the LiIon battery was dead - would not charge past 3%.
Ordered iPhone Liberation Kit, Pry tools and new LiIon battery from ifixit. The day the bubble wrapped packet arrived, I followed the very intelligent instructions to remove old battery and replace with new. In about 20 min max taking it slow and easy and cautious.
Only hesitation I had was trying to unscrew the tiny Philips screw for the battery connect plate! Found the right size Philips driver and the rest was easy - well except for relacing that very tiny connect-plate screw: it kept been pulled to the magnetized part next door!