What to do with 3-Star Units/Weapons?

I've been playing for 3 days, reached level 17 with my main class, and have a solid grasp of the game, for now. However, throughout this time I've hoarded every single 3 star equipment I've acquired, and now it's becoming detrimental to my inventory and storage. Do I sell them, use them as enhancement fodder, or keep them and hope a swap shop of some type is implemented?

If they have the bonus effect where they give 450 exp to enhancement keep them. Otherwise sell them on the market or vendor. What i've been doing.

Use them as enhancement fodder first since grinding weapons and units to max level can take a lot of resources. If you don’t need the enhance fodder and if you have premium sell them on the market as they make a decent stop gap for newer/unlucky players. If you don’t want to sell them on the player market just trash them.

Thanks for the responses, I've been keeping the silver/gold primm swords to enhance my 4 stars so I'll sell the 3-star weapons, but I'll keep the units since enhancing them is less forgiving.