vq wrote:

When the plumber drained the old water heater before removal, strangely
not much sediment came out the hose.

The mineral deposits inside the tank tend to bond to the side and bottom of the
tank, so I'm not sure that flushing does a whole lot of good. Some tanks come
with a corkscrew style dip tube that purportedly swirls the supply water, but
again, I suspect that's more marketing fluff than reality. Unless you are
filling a bathtube, there really isn't enough demand to swirl a 40-50 gallon
tank of water.

Truth is there are only a handful of water heater manufacturers in the US and
there is no difference in the quality of the warranty vs the length of the tank.
The preimum paid for longer warranty heaters just goes to pay the couple of
extra claims they get and to help increase the margin.

If you have hard enough water that mineral buildup in the heater is a problem,
you really should have a softener.