So, theoretically, if you haven't flushed your hot water heater in 10+ years, should you start now, or will that just invite problems?
Asking for a friend.
If it is not leaking, high probability no- it will not harm it and only then help keep it going.
Electric are more "resilient" to dealing with sediment because of where the heating elements are located, while gas, the burner...is on the bottom and thus has to heat /through/ the sediment more so than electric.
doing a complete refresh of your water heater should not harm it...like a transmission flush for a car could, where the build up can "be the seal" etc. - in standard electric water heaters - unless there is scale that has /really/ done a job on the element port threads - you will only be helping your heater.
Again its a very basic product.
Even at HomeDepot / Lowes prices - elements are like 20-40$ and 10-15$ for the element socket. order a segmented anode rod with socket from amazon for 30-40$.
If you do not know what heating element to get... and you can go a time without hot water... just order the heating element socket online with the rod/socket - drain it/flush it. Then take out the element and take it to HD/Lowes with you and essentially match the size, or show it to a bro in plumbing and they will get you the proper ones.
the elements are screwed in and should be no problem. they are connected to the thermostat with a + and - wire that usually is a standard philips head screw.
Always turn off your breaker and power and turn off the water supply.
So, like 250$ and your water heater is essentially new - all the working parts are replaced. The tub is really just that...a tub... and it will last for a very long time as long as you keep feeding the water anode rods to eat and not your actual tub.