I didn’t think the 64GB E-Series cards were out till August.
The biggest cards are usually the best price per GB.
The interface is the part that wears out and the E-Series cards are guaranteed for 5 years based on one insert per day as I understand it. I suppose the nature of what and how you shoot on average would enter into the equation at some point. If you find you normally load a card to 20 GB and then end up dumping the footage at that point it would make no sense to use a 64GB card. If you find you often capture 40 or more GB on a card before dumping then you should be getting the 64GB cards.
My cards go for long periods of no use between shoots so the one insertion per day doesn’t effect me. I go for the biggest cards available so I can shoot in 1080 most times and not have to worry about running out of storage.
“thou can not stir a flower without crumbling a star” ……Henry Wadsworth Longfellow