Bring Cash!
Since a friend willing to be DD is one of the rarest gifts god can bestow, you'll be taking cabs everywhere. Cabs that basically only accept cash. So before you triple the length of your trip to have them stop off at an ATM, do yourself a favor and get yourself a money brick. And after that, make sure to ask how much the cab will be before even stepping foot onto that van's mystery stained carpet. Otherwise, expect a less than friendly rate at the end.
Note: Uber does exist, but prepare yourself to wait.
[Photo via @secretagent212]