Board Thread:Game Discussion/@comment-10324144-20130620185755/@comment-9932745-20130620210019

If you're not trying for the chance for event cards, you can wait until you get your reward cards to upgrade. Either you can upgrade during the downtime between events or wait until the next event starts and open up your leftover medals. They're worth more during events when you sell and/or use them as upgrade fodder. Also, your leftover event medals become normal medals, so you don't lose them after the event. I usually bypass the discount and upgrade during the downtime so I can hit the ground running when the event starts. It's up to you. Good luck and nice job on the 2nd tier placing! 3 more hours!