Your suspension guy is talking rubbish, assuming you only want to change the springs and keep the standard shocks as Ed says the rear is a 15 - 20 job each side, do not attempt the fronts unless you access to some professional spring compressors as the strut disappears into the shock and the amount of compression the spring requires to enable reassembly of the unit cannot be achieved by normal claw type compressors, I know from fitting Eibach springs earlier in the year,
Shipkiller has a how to on the front springs and Cj10jeeper recently posted on how to change the rears
If you access to the proper tools its a mornings work at the most.