Some time ago Consumer Reports cut open water heater to check the insides.

As I recall, the 9 or 12 year warranty heaters contained much better
insulation that the 6 year warranty.

If you decide to replace it...
wrote in message
ups.com...
No hot shower is a biggie for us, less important for tub bathers.

So you have gone 3 days without hot water, spent 20 bucks on a anode
rod, how much will the vinegar cost, you will need a LOT to really
clean the tank since the rust MIGHT b formed in the bottom but then
again MAY be near the top

Letus know how it goes your family must be patient I KNOW mine never
is