Are follower items worth keeping if I never play solo?

My girlfriend and I bought Diablo 3 specifically so that we could play couch co-op mode on Xbox 360. We have no interest in playing online or either of us playing solo. Since we're always in co-op mode, we can't do anything with the followers.

For awhile we've just been stashing all of the follower-only items that we pick up with the intention that MAYBE one of us would get around to playing solo strictly to beef up the followers. But lately we've been thinking that would be a total waste of time since the followers never join us anyway.

So is it better to just salvage these items as we find them or is there any possible way of using either the items or the followers in co-op mode? (Also, just last night we picked up ROS for Xbox 360 if that makes any difference in the answer.)

Since RoS there is a new level 70 set: Asheara's Vestments.

And the 4-piece bonus is:

Attacks cause your followers to occasionally come to your aid.

So basically if you craft this set and use it, all 3 of your followers will sometimes (actually pretty often) join you, including in co-op mode. So if both of you have this set, you might end up with 6 followers in total.

To answer your question: keep only the best ones you find. And since you can't really use this set before level 70 (unless you reroll some stats for the reduced level requirement), salvage all which are not level 70.

Also, do not forget that there are 9 follower-only legendaries:

• Templar
  • Enchanting Favor
  • Relic of Akarat
  • Hillenbrand's Training Sword (1)
• Scoundrel
  • Skeleton Key
  • Ribald Etchings
  • Slipka's Letter Opener (1)
• Enchantress
  • Hand of the Prophet
  • Smoking Thurible
  • Vadim's Surge (1)

(1): These items are Season only. Source