A ‘full set’ of eyelash extensions essentially means adding extensions to every mature eyelash on the upper eyelid from corner to corner. This may vary considerably in number from person to person (from 70 to 100 typically). The full set will take about two hours to apply. The full set will look as thick and lush as possible.
A ‘half set’ (also sometimes called a ‘semi-set’ or a ‘demi-set’) also usually involves adding lashes from corner to corner, but one every other lash (perhaps 35 to 50 lashes). This should take about one hour. This may look more natural, and it is cheaper to buy.
Another way of doing a ‘half set’ is to only add lashes to the outer two thirds of the eye.