Board Thread:Question and Answer/@comment-67.249.65.41-20160210093730/@comment-25435121-20160210203227

finish this event to collect what you want, then next event perhaps alternate between the event map and the regular campaign.

Buying the +5 increases do help, but if you don't clean out your deck, or compulsively try to save every card, then it will continue to be a problem.

The most cards you can have is currently 500 (300 main deck, 200 in collection pages) but the game has over 4000 cards in it (and growing every event). You are guaranteed to not be able to keep everything.