Adjusting temperature setting on a Bradford White gas water heater

This unit is about 18 years old and I must say I have been very happy with it, and when the time comes, I will replace with another Bradford White. The only maintenance I&done thus far is to replace the dip tube and flush the tank a few times to remove sediment from the bottom of the tank. I also replaced the factory drain valve with a 3/4" ball valve which allows better flow when draining water and sediment out of the tank. I changed the temperature setting for a few reasons: 1 Main reason was to adjust water temperature so when operating a single handle faucet in the center position the water isn&too hot. 2. Reduce how hard the tank is working considering it&age. 3. Save some $$$. Just an FYI on dip tubes. It is connected to the cold water inlet and runs down to the bottom of the tank. That way cold water entering is added at the bottom while hot water continues to flow from the top. When the dip tube is broken, the cold water entering the tank mixes with the hot water at the top and what you will experience when showing is hot water followed by not so hot water. This will fool you to believe your tank is no longer working, but in reality it has a full tank of hot water. One thing I have not done is replace the sacrificial anode which is a magnesium (or possibly aluminum) rod in the tank that basically protects the lining of the tank by allowing minerals in the water to attack it instead of the tank. These rods typically have a life equal to or slightly greater...