I have a gas water heater at home & electric at my place in the mountains. The mountain home gets drained several times a year, when ever we leave & it might get cold enough to freeze & burst. The gas water heater does not have any freezing problems, but I still drain it a couple times per year…. every time I drain it I get sediment & hard water deposits. This crud will usually fill a two pound coffee can or more, and usually requires several drain/fill cycles to wash out. I remove the drain valve, replace it with 3/4" PVC pipe routed outside, and turn the water on, draining & filling till it stops sending out lots of chunks. These chunks usually plug the drain hole in the tank, so I put a 90˚ elbow close to the drain connection. This 90˚ ell has a .040 hole hole drilled in it, with a .040 stainless wire fed into the tank drain. When it plugs, I use the wire to "roto-rooter" the chunks, dislodging them to wash out the pipe. I have always drained my water heaters regularly, and I've never had to replace one.
The gas heater in my first house was 18 yrs old & still working when I left, and the one in this house is now 25 yrs old, and the electric at the cabin is 27 yrs old & still going strong.
Regular draining & flushing seems to work for me.
P.S. Almost forgot, the gas/electric in my toy hauler is 11 years old.