When living on my boat down island I got in the habit of changing all my anodes (5) at least twice a year. I was prepared to do the same in my Airstreams. I was told sternly by two different experienced RV mechanics under no circumstances to use an anode in modern aluminum RV water heaters. Not necessary and can actually be harmful.
One also told me that he did not recommend the use of brass plugs with built in drain. Reason, it hampered a good forceful drain of the tank. Gunk and other goodies might not be sufficiently flushed from the tank. I currently have a brass drain in mine and plan on removing it next tank flush.
WBCCI 10656 Southeastern Camping Unit
Associate European Unit
2006 Safari LS 23 ft
Formerly 1964 Bambi II
"I got a fever and the only prescription is more cowbell"