User blog comment:Methredhel/Increasing Card Deck Holdings/@comment-5526558-20121030003426

yes, the old system used to be by gallery, but now its by card level. everybody from the gallery era got to keep their increase though, so anybody with abnormally high card space got it thanks to that.

like i said, the system is by level now. every 35 levels+1 will increase your space by 5. it works alongside the old gallery increase, not on top of it.

level 36 gives you 55 cards, level 71 gives 60, level 106 gives 65, etc.

if you have a max of 60 cards thanks to the old gallery system, you will have to reach level 106 to increase it further. reaching levels 36 and 71 will do nothing since they increase to amounts below what you already have.