I agree that a double boiler is not a necessity, but it is an inexpensive luxury that I like tremendously. Among other things I've heated glue in plastic yogurt containers in the microwave, and mussel shells beside an open fire. In the upper part of the double boiler I leave a small amount of dried glue at all times. Since the boiler comes with a lid, I can keep it covered once it is dried, and I can keep it on a shelf in my shop indefinitely. No problems with mice, dust, etc. When I am ready to heat it, I put a little water in the glue, and put water in the bottom part of the boiler and it is ready to heat. I can heat it on the kitchen stove, the barbecue grill or my Coleman stove in the shop and never worry about scorcing it. Like I say,,,,, not necessary, but I like the convenience. Curtis