Its really annoying how all modern appliances .. water heaters included are designed to fail in 3-5+ years... (or in some cases 1+ years)
My old heater was caste iron and glass lined... and when i left it was a a nice 45years old .. and could heat 50gallons in under 15mins to 175f....Modern heaters would explode if you tried to heat water to that temperature. and generally take 30+ mins to get to 125f