What is the ideal size of the FUE punch?

Everyones hair caliber is different so the punch size needs to be a balance between making the smallest scar possible while being able to extract the graft intact and some insulating tissue around the graft. I start each case testing different punches, revolution speed, and type of punch. I don't go above 0.8 mm, preferably a 0.7 or 0.75 mm. Remember typically the purpose of doing an FUE is to camouflage the donor area for people that want to wear their hair very short. The punch size and distribution of extraction is critical to this end. 

The FUE punch size will vary from patient to patient. Your surgeon will ultimately decide which FUE punch is ideal for your hair transplant.

There is no one right answer. Each case requires matching the right punch size to the hair caliber of the patient. Generally, we use a 0.80-0.85 mm punch for Caucasion patients, and 0.90-0.95 mm punch for African-American patients due to the curl of the hair within the dermis. Clinics which use 1.0 mm punches or higher (as with the ARTAS machine) should be avoided due to excess scarring.