Board Thread:Questions and Answers/@comment-1031179-20161103035428

He never used an armor skill. Does leather armor not require a skill slot?

In Sword Art Online Progression volume 2 it says when he was at level 16 he had four skill slots, and they were filled with one-handed sword, martial arts, search, and hiding. So no skill slot for armor.

It says Asuna had four slots as well, one of them light metal armor since she wore a metal brestplate when out adventuring. 