I have used the same anode rod in my Suburban water heater for four years and it is in the same condition as the day I put it in. Why is it not being depleted.
Our TT has an Atwood water heater and it says it has no anode in it.
Judging from our home water heater and the liquid rust we call fresh country water, I doubt that we would miss it. Our first home water heater lasted 20 years the second is going on ten years; I doubt either has any anode left.