Just sharing a recent experience.
The night before leaving for a trip, I had the fridge running on propane and batteries (no shore power). I went out to lock things up and I heard this load flow noise from the vicinity of the propane hatch (passenger side). I had never heard such a sound and given the fridge used VERY little propane, I investigated further. Short version of the story, the first stage of my regulator had failed and propane was dumping out the vent hole.
So, I shut off propane and we started our trip with a large cooler filled with our food and ice in the back of the toad.
Along the way to our destination I was able to stop and buy a new regulator at a RV store. Cost me about $50. I quick and easy to replace and I was back in business, less the money and about 1/4 tank of propane.
Lesson learned for me is to buy a spare regulator and carry it with us. From my research these things fail fairly often and I don't ever want to be stuck without propane during one of our trips.
The regulator that came with our unit lasted less than three seasons, one like this Amazon.com - Mr. Heater F273763 Propane Two Stage Regulator 1/4" Female Pipe Thread(inlet) X 3/8"Female Pipe Thread (Outlet) - Gas Pressure Regulator
This regulator was highly recommended so I just ordered one as a backup.
Amazon.com: Marshall Excelsior (MEGR-295) Compact Integral Two-Stage Regulator: Automotive