45 minutes - 2 hours
The headphone jack was defective on ipod classic.
Hard to get back off, this a question of the correct selection of tools, the blue plastic leavers are a bit crap! Good to have a few 1-2" putty knifes & a few levers to insert into gaps once you have started to create a gap.
Ipod work as it should again.
I would only tackle if you are comfortable with small fiddly assembly type work & have a steady hand.
Have a good look at the resource available on the net first.