[CaberTosser]

My experience pretty much mirrors thepilotcock's except in that I've changed a few residential anode's, but relatively few considering the 31 years I've been at it. Commercial tanks are more common for anode replacements, (sometimes I'm just changing them in insulated storage tanks that are simply volume storage with a circ pump) but then those type of buildings generally have management following established maintenance procedures.

I too like a full port ball valve on each heater drain attached with a short brass pipe nipple with a hose adapter and a screw on tethered cap & chain. New heaters have drain valves that need a tool (screwdriver or wrench) to actuate them to keep little people safe from the hot water, I tighten on the cap beyond hand-tight for this reason. The full-port valve allows for more rapid flushing of the tank which will stir up more sediment.

Some tanks with longer warranties come with dual anode rods, one will have its own threaded port in the tank and the other will be suspended from the hot water outlet nipple. These are available separately or as replacement items and can be beneficial. Some manufacturers or suppliers offer longer warranties where the only difference is paying more money for the warranty extension, no additional anode rod or such.

Last spring I had clients whose hot water was quite rusty, they had dual power-vented water heaters piped in series. I unscrewed the anode rods and each was dissolved down to a metal core rod which was the source of the rust (I was curious why it was not a stainless steel centre core, but I digress). I replaced the anodes and flushed the tanks repeatedly and they were OK, a good savings considering what a power vented 50 and a power vented 75 would have run them combined. (I may sell them a boiler and stainless indirect heater when they do cave on them, its a bit of an odd set-up presently with one heater upstream of the 2nd serving their floor heat). Anyways, the reason their anodes were so corroded was their excessively aggressive water softener, it was amusing as my product rep for their brand of water heater immediately asked if they had a Kinetico softener when I described their anode condition, so its a known issue. The house was not that old, I think perhaps 6 years in a nice neighborhood (West Springs).