I wonder if that's our problem. The 50 gal natural gas hot water tank in our house tends to last 8 years. We've gotten 2 replaced by the 10 year warranty (just paying labor to install a new one). We have very high water pressure.
We've liked the natural gas hot water heater because it has always worked when we had a power outage (a hot shower in the cold dark bathroom is acceptable). We've been here 30 years and have 3-4 outages a year. Because of where we are hooked to the grid, we tend to be more affected by outages and ours last longer as our service is often the last to get repaired.
But now that we have battery backup in the house (2x PowerWalls) along with the PV on the roof, I'm thinking the next time I need to replace the HW tank I'll go with not powered by natural gas (still have to convince the Mrs. of that).