I know they can't use enchanted weapons like bows and swords. After a battle I don't see the recharge level ever been drained.

So I made a few neckness rings or enchanted armors for fortify health and archery. Do they work or am I wasting time and resources?

http://www.uesp.net/wiki/Skyrim:Followers#Follower_Equipment

The above page has details on what they can benefit from wearing
Haven't noticed with enchanted weapons but Eola is happily using up charges on a variety of staves

THANKS !!!