honestly i never have any problems of card breaking in half even when im using the cheap ol' pasar malam short wallet.

even used LV short wallet with loads of card still ok till i lost it (still bitter till today)
nowdays im using a long wallet and always at the back of my pocket and not a single one of my card breaks.

unless ure shoving everything inside ur wallet i dont see the card will break easily.

just do some cleaning once a while and throw away any of the receipt that u keep inside the wallet or keep some unused card some where else.

honestly its weird, i got my id card, licences 3-4 atm cards, discount cards and misc. card and name cards mostly in my wallet and my card slot put it in my back pocket summore... but never once (touch wood) of them breaking. but the slot are quite deep so maybe its one of the reason.