If you ever find that you're not getting any hot water out of the tap -- and if you go to check out the water heater and notice that the burner isn't on -- and you open the little door to the combustion chamber at the bottom and find that not only is the pilot light out but there's quite a bit of rust in the chamber -- and then you realize that there's a nice little puddle of water down there -- you can pretty much say goodbye to your water heater. And $400.