Repairing and iPhone 3GS and iPhone 4 in one long night!
After almost 2 years, my son's iPhone 3gs was seriously ill. It needed a new mute button and battery. Also, my 2-1/2-year-old iPhone 4 lock button was not working and my battery was not even lasting one day, so it was time for an upgrade or a repair. Since we were changing providers at the same time, this was a good way to save money.
The repairs were slower than I expected, and I was working on faith that the instructions from your site would be detailed enough to allow me to do it and not forget any steps. I was able to replace the mute button and the battery in the 3GS in under 2 hours, I believe. The iPhone 4's power and sensor cable, however, took longer.
Patience and perseverance are required. I found that I needed to zoom into the photo at the end, especially for putting the mute button and power and sensor cable back into the phone.
The iPhone 4 repair was tricky, and I had to use a small pick at various places to get the adhesive pads out of the phone or off the old cable. The ear speaker sticker/pad was torn in half after removing it, so I had to glue it back together to get the speaker to stay when I put it all back together. I was relieved that everything still worked once I put it all back together.
I was also worried that the 3GS mute button was not the problem, but the underlying circuitry. As it turns out, it was the button after all. Perhaps it was a defective part, because the socket into which the actual switch was inserted was broken, causing it to work only sometimes.
Another piece of advice is to show your kids that you are taking the time to fix rather than throw away. Some day they will remember that and think twice about being wasteful.