You will need at least 2-3 weeks growth in order to achieve a clean wax, this does vary from person to person. For your first wax we would definitely recommend 3 weeks growth. It is REALLY important for the hairs to be long enough so that the wax can grab them otherwise hairs will break or will not be removed completely. If your hairs are not long enough we recommend rescheduling otherwise you may be disappointed with your result. We would ask that hair be trimmed to about ¼ of an inch long.