When my wife and I got married back in '66, we bought a New 12x55 Mobile Home. It had a 30 gallon electric hot water heater. It was fine for the two of us. We lived there for 12 years. During that time, I replaced the heating element once...and then later, replaced the entire water heater.
The first time..It seemed that the heating element corroded through... and self destructed. The second time it failed.. The original heater tank was alleged to be "Glass Lined"...whatever that meant..perhaps the inside of the heater was "Glazed" with a ceramic...Anywho.. It was cheap enough to just replace the entire tank...I think it was about $75 for the new tank at the time..Did it myself.
NB