10 - 30 minuten
First off, I replaced my battery in my 4S and my friend's battery for an iPhone 4. I will mostly just cover how it went for my phone. After about 2 and a half years with my iPhone, the battery was just garbage. I think that's about the regular lifespan of a lithium battery. I was considering getting a new phone, because of various other problems with my phone as well, but I am so glad I replaced the battery!
Very smooth. The instructions were clear, the pictures helped greatly, and it went off without a hitch! Only one small problem with my friend's battery switch-out was that I somehow got the batteries mixed up and at first had taken the old one out to then put it right back in! Oops! It would have been helpful if the receipt I got with my purchase came with a serial number for the new battery on it too. Or it would also be helpful that I could use my brain and not mix up the batteries. Oh well.
well, if you are on this website and are wondering if you should try fixing a product yourself, I say go for it!!! It worked out so well and it was so reasonably priced!