45 minutes - 1 hour
My iPhone 4 had a bad dock connector which caused have phone to have no sound.
the Process was simple compared to other iPods i have taken apart. the plastic opening tools make the removal of fragile components easier, perfect for me who is good at screwing up and breaking things. it took 15 minutes and the phone is like new.
If you phone breaks go to ifixit and get the tools and components you need.
P5 Pentalobe Screwdriver Retina MacBook Pro and Air
iFixit Opening Tool
iPhone 4 (GSM/AT&T) Dock Connector