What bothers me about water heaters is that several years ago the were built to withstand up to 175# psi, and I sold thousands of 175# psi relief valves as a teenager in a hardware store. Fast forward several years, and relief valves cannot exceed 150# psi, and these things drip and pi$$ al the time. And now they want you to install a thermal expansion tank also, and they added more insulation to be energy efficient. Every tank I sold as a teenager, and the tanks I purchased up to 10 years ago, warned not to use insulation kits as they shorten the life span of the tank. Tanks now run $500 dollars or more.