Francesca Britt, of Villa Maria College, asks :-

How often does the skin on my face change layers?

David Young, a Dunedin dermatologist, responded.

The outer layer of skin, the epidermis, is constantly renewing itself on the face and elsewhere. In the basal layer of the epidermise the cells divide and one cell remains to continue replenishing the skin and the other gradually transits through the various sub layers of the epidermise until it is "flaked" off the surface.

This process from cell division in the basal layer to when the cell is flaked off the skin surface takes approximately 30 days though it can vary.