We always take some cash, US and local currency (if possible). Also, we take two credit cards each - one of the same card (main) that we can both use and then each of us takes another (but different) card. So, if one of us loses our wallet, we can cancel the two cards in that wallet and still have one viable card to use for the remainder of the trip.
DH nearly lost his wallet in Cancun due to pickpockets. But he felt it and chased the culprit who dropped it and ran. We got very, very lucky!