Is it better to run a tab or pay as I go?

The answer

Both work, and the better choice depends on how closely you want to track what you order. A tab is convenient because you do not have to pay for every round, but it is easy to lose count of how much you have had and spent. If you open a tab, keep track of your drinks, close it before you leave and review the receipt. If you are in a group and want separate checks, tell the bartender at the start.