Available on Project MUSE and JSTOR. Online access to Contemporary Literature is available as part of the Project MUSE collections. All back issues of Contemporary Literature beginning with Vol. 1, 1960 are available online through the JSTOR digital archive.
Many manufacturers recommend water heater anode replacement every two to four years depending on the hardness of the water that passes through the tank and the quality of the water heater lining.
You're spot on about draining your water heater. Very good Ible. Many years ago I had to replace my water heater. Where I bought the heater the technician told me besides draining the heater, replace the anode rod in the heater every 2 years, and in most cases you'll better than double the life of your heater. He told me he has the same water heater in his house for 23 years. I've been changing mine every 2 years.