This very much depends on the size of vehicle & the amount of Paint Correction required.
Stage 1 Paint Correction (Removing very light defects) on average this takes around 6-8 hours.
Stage 2 Paint Correction (Removing moderate Scratches, Scuffs, Swirls etc) on average this takes around 8-10 hours.
Stage 3 Paint Correction (Removing heavy Scratches, Scuffs, Swirls etc) on average this takes around 12-14 hours but in some cases can take 2 days depending on the size of vehicle & amount of correction required.