Everyone's situation is different. Difficult to quantify for your particular situation. It has less to do with water heater design per se than it does with individual situations.

But, to answer your question, yes. It will extend the life of any water heater. How much? Depends....on factors that you will not be able to determine. However, if you think you should expect 20 years out your residential water heater -- any mfgr's residential water heater -- I suggest you make a mental adjustment.

I flush mine twice a year. They go bad anyway, in due course. More important IMHO is making sure there's a place for the leaking water to go when it does go bad. They all fail the same way -- they leak. If you're on a slab like I am, you'd better be sure there's a safe, no-damage pan and drain-path underneath the unit.

I think a lot depends upon water quality and chemistry. I've lived in houses where the water was pretty nasty and the heaters only made it 5-7 years. My current heater (with very good water) is 23 years old. I've never flushed a water heater, but I know that it is recommended.

"I think a lot depends upon water quality and chemistry."

Um...well, yes...like almost all of it.

And this user is supposed to objectively/quantitatively determine the service-life of his personal water-heater exactly how based on this? Somewhere between 5 and 23 apparently?

Repeating the last line in my own response: "More important IMHO is making sure there's a place for the leaking water to go when it does go bad. They all fail the same way -- they leak."

Ignore at you peril.

lostinit: yes.