Properly speaking I don't like managing my followers inventory. Ideally I'd just focus on my own character.

Often giving your follower new gear makes him/her look worse and simultaneously some of the identity is lost. Original clothes often look the best.

Serana after I gave her elven armor looted from Vyrthur:

http://cloud-4.steampowered.com/ugc/532876420474663032/C8864239E0FE8E910AC5E8CA4CA0F2F9EEB86CAC/