On 2-14-2022 my 50 gallon water heater decided to burst. It had served me for 10 years and was in the house when I moved in, so I suppose 10 years is a good lifespan without any maintenance.
I stepped inside the house from my workshop at 3 PM and was greeted by the sound of a rushing mountain stream! Water was spreading across the floor. I quickly turned off the inlet water via a handy valve provided for that purpose, summoned my son to help and got busy mopping up the water. Having stained concrete floors rather than carpet was a huge win in this scenario.
After measuring the heater, off to the store we went. Lowes has a minimal and unsatisfactory stock, so across the street to Home Depot we went and found a Rheem Performance Plus 50 gallon heater of the same height (57 inches) as the original and with all the connections up top. By 8 PM the same day we had the new unit in place and working and the house generaly cleaned up. The unit cost $739, and with tax the total was $800.
I will note that I was hugely fortunate to be home and to discover the burst shortly after it must have started. As for maintenance, I'll note that it is all but trivial to drag a hose into the house, connect it to the drain at the bottom of the heater, and flush out sediment. They say that if you do this, a tank type water heater will last almost forever.
The big problem is the electric hookup. A standard tank type heater has a 30 amp 240 volt breaker and uses 10 gauge wire. Note that with a 4500 watt heating element, such a heater will draw less than 20 amps, but this is how things are done. A tankless heater requires a 60 amps breaker (or a pair of 40 amp breakers and an extra pair of wires), and the wire needs to be 8 or even 6 gauge to handle the current. The need to pull new wire is going to keep me from installing a tankless, despite all the other advantages. So I flushed a small amount of sediment from the 30 gallon tank water heater in the guest house "loft" and swore to do it regularly.
Tom's Home repair pages / tom@mmto.org