I had a customer that was curious about his water heater. It was running but older, and he’s had questions. Based on the signs, such as: 1. Burn marks around the burner assembly door 2. Water heater was over twelve years old 3. It was also showing signs of inconsistent heat. The area was also known for its hard water. After some discussion I advised him to change the water heater before it became a problem. He agreed. When I pulled the water heater it had melted a perfect hole through the nylon drip pan and the flooring was burned. Crisis averted.