I just went thru a tank replacement. Two weeks ago, while getting ready to leave on a trip, I flipped the bypass valve and discovered the tank didn't survive the polar vortex (we hadn't used the water heater yet this year) when water pressure dropped to zero at the kitchen faucet, and the pump was running nonstop. After turning off the pump, we found water pouring out of the compartment on the outside, and water under the cabinets.
We were lucky the leak was caught immediately, and I was able to dry things out (multiple high-speed fans blowing into the water heater compartment) fairly quickly. Had it gone unnoticed for weeks or longer, I'm pretty sure the floor would have been destroyed.
New tank was $169 on Amazon, and I did all the work myself, which took a little over two hours to take out, swap tanks, and re-install. There's a really good 45 minute video that does the step by step on the Atwood.
I'm pretty comfortable with plumbing, which probably made the job easier, and I also took the opportunity to swap out some of the older PEX fittings. If you don't have the tools for PEX or feel comfortable with working with gas or water fittings, find someone else who is.
