4 wallets: one for non-MS daily use, one for making MS purchases, one for gift cards and unloading them, one for sock drawer.
I use a passport wallet for holding gift cards and unloading vehicles, it has a lot of room for holding cash, receipts, gift cards, receipts, BB/PP/Tmob cards and what have you. I've gotten it 2 inches thick, and still had room for more, though at that point it doesn't fit in any pocket I have.
I track purchases separately. I've looked at Milenomics most recent system, but I think it can be improved on. For now, I churn in small batches.