I use a thermometer in my barrel and it has saved me many a times. Turns out where I was using my barrel just outside of my patio cover, there must be a wind vortex that effects the air flow as I would get all kinds of temp swings and have all kinds of issues. I moved it farther away and have taken it camping and it runs very consistent. If it weren't for the thermometer I probably wouldn't have figured it out and I likely would have gotten rid of the thing thinking it was the barrels fault or issue. I know it's supposed to be a set it and forget it cooker, but there are many factors that come into play, outside temp, winds, charcoal moisture content, amount of grease droppings extinguishing the coals, etc... so it's nice to monitor what's going on inside so you don't have these kinds of surprises. Just my experience for what it's worth.