I just got back from six weeks on the road. We went through 1-1/2 tanks during that time. We used the propane for the following:
1. Furnace about five mornings to bring the temp in the RV from 55 up to 65.
2. Propane turned on to keep refrigerator cold while in motion. Typically 4-6 hours per day.
3. Hot water while dry camping, about 20 days.
4. Cooking on the stove top for breakfast and dinner almost every day.
5. Using the oven for 2-3 hours per week.
So, we had a lot of use and still didn't need to fill up in six weeks. However, during cold weather camping, we go through a bottle every 4-5 days with the furnace.