Originally Posted by Masterwolf

No real point in keeping them. As the game goes on you will be swimming in them. Use them for the extra gear slot/skill ups. Not to mention all the resources you would waste on leveling a second copy when those resources could be better spent on leveling your initial 4* and higher units.

Ah okay good points. I guess equipment and stuff will eventually make up the difference as the game progresses, so it'll be good to have those slots. Would you recommend doing the same for 5 and 6 star units too?