If your propane tank for your gas grill does not have a gauge or indicator and you're not sure you have enough propane left to get dinner on the table, there are two easy ways to determine how full - or empty- the tank is.
If the tank is cold, pour some very hot water down the side of it. The water will heat up the empty portion of the tank; the portion of the tank holding propane will remain cool.
If it's a hot summer day, just run your hand down the side of the tank. When you reach the cooler section of the tank, you'll have discovered your propane level.
And of course, if you grill a lot, you should have two tanks; make a habit of swapping the empthy tank for a full one on your next trip to the grocery store.