How long does a full-face laser session take?

Planning a full-face laser visit around a lunch hour is the mistake this question invites. The published figure is longer than a lunch hour, and it covers only the treatment itself.
The time the source gives
Here is what my.clevelandclinic.org says about duration. A partial-face laserabrasion takes 30 to 45 minutes, and the full-face treatment takes 1-1/2 to 2 hours.
The cautious reading is that the source gives treatment time and does not say how long the whole visit runs. Leave extra room on both sides, and do not stack a Mt Olive commute or a work meeting right behind it.
Partial face or full face is not your call
Do not pick the area to be treated yourself. Whether a partial-face or full-face approach fits is a decision for a trained clinician who has examined your skin.
For background on what the session involves, read Laser Skin Resurfacing | The Aesthetic Society and the benefits, side effects and average cost overview. If you are still weighing options, how dermatologists treat sun-damaged skin and a guide to wrinkle treatments cover the alternatives.
Confirm the length before you clear the day
A session time is a planning number, not a guarantee. Ask the clinician to confirm the expected length for your own treatment before you clear your calendar around it.