It all depends on the size of the fire pit and how often you use it. If you have a small fire pit, you can expect the propane to last anywhere from 6 to 8 hours. If you have an enormous fire pit or use it more frequently, the propane may only last 4 to 6 hours. However, there are some ways to extend the life of your propane, such as using a windscreen or placing your fire pit on a raised surface.