It is a very old topic, however there is no such thing as scar free.
All depends on the punch size, the extraction pattern, healing characteristics, skin colour... and experience.
Here an example of what we believe is the difference in experience, extraction pattern can do under similar conditions and virtually same number of extractions.
In some cases we use at our clinic 0.7 for fine hairs and in very rare case we use 0.9 or 1.0 mm when dealing with very thick hair or with patients with over average hairs per graft. Mostly we use 0.80 mm punches.
Left picture : Non Belgian clinic, donor area shaved about 2 years after procedure, 2000 grafts. Extraction tool size used unknown.
Right picture: Prohairclinic, donor area shaved about 1 years after procedure, 2000 grafts. Extraction tool size used 0.80 mm.
On the left you can clearly see the extraction pattern is less then ideal combining adjacent extractions (or attempts of extractions).
Although both where harvested 2000 grafts, it is clear not the same optical result.
Alarming however is that many patients now seek cheap and fast procedures knowing that their donor might be damaged or depleted after just a single session. Their reasoning is (falsely) that the damage like in the left picture is easily fixed using SMP ¦ it is NOT!