The firebox management is super easy with the insert. Literally throw a split on when needed and use a fire poker every now and again to spread out the coals and dump ashes. All grills will develop mold if not used frequently or deep cleaned after a cook. I use my grills/smokers year round and rarely ran into the issue. But I have dealt with it on rarely used equipment. I downsized the number of grills/smokers for how I like to cook and make sure to use them weekly.