Board Thread:Game Discussion/@comment-9713390-20130614000458/@comment-9723936-20130616080347

I sell all R1 cards. I use R2 cards to upgrade R3 cards, or R4s when I get them. I then use those upgraded R3s to upgrade Event Cards, or special R4s that I want to keep. That way I keep My base nice and clean, and still have a lot of upgrading power when I need it.