I'm guilty of ignoring my water heaters. Had my backup start to leak and it cost $1500 to replace. So I immediately bought a new anode rod for my primary tank. Drained/flushed it and replaced the old rod which was completely gone. It was an easy task but you will need a cheap impact wrench, 1 1/16" socket and chain link anode rod to make it easy.

It's something you need to do every couple of years. But I never do it.