It has long been recognized that density is largely dependent upon blade size: a smaller blade results in more slits in any given area. Dense packing is defined as placing grafts at 28 or more follicular units (FU)/cm2. As a consequence of stereoscopic dissection the physical size of grafts has gradually decreased. These smaller grafts require smaller recipient slits, and today it is possible, in people with smaller and shorter follicles, to densely pack up to 45/cm2 two-hair FUs (sometimes more) and still obtain consistent growth. For example a 0.85-mm blade set at up a 0.95-mm deep is generally safe at 45/cm2. Two-hair FUs in Asians usually require a 0.95-mm blade set at a depth of 5 mm. Even with such a slight increase in blade size and dense packing at 45/cm2 may reduce growth in some individuals. Resonable starting densities for most surgeons are at around 25 to 28 FU/cm2, and these numbers may be slowly increased if there are no growth issues. For beginners, or those with new surgical teams, I would suggest that you start with whatever the team is comfortable with and do not dense pack until the skill level improves. There are wide variations in the manual skills of both surgeon and teams, so that what is safe for one group may be unsafe for another.