Here's the rule: Buy a drink when you walk in. Then don't worry about it as long as tables are free. Because you're not displacing any customers. Once you gl

Here's the rule: Buy a drink when you walk in. Then don't worry about it as long as tables are free. Because you're not displacing any customers. Once you glance around and notice the place is getting kinda crowded, walk up and buy another drink if yours is empty. That way you're not costing them any business.