5 - 30 minutos
iPhone4 wouldn't take a charge. Took it to the Apple store and they said it probably wasn't the battery and said I would need to buy a replacement phone for $149 (and I would lose the info since I hadn't backed up). Ordered the battery for $25 on iFix it and it worked perfectly.
The repair was extremely smooth. Although the philips screwdriver I ordered was a tad too big for the screws... but it worked. The whole repair took 10 mins. tops for a noob like me.
Always check iFixit. Couldn't believe how easy the repair was and how much I saved. Apple was charging $80 for the same battery.