We moved into our current 1964 house in 2011, and have a 50 gallon tank. My wife complained about the shower hot water running out after 10 minutes (she doesn't know what a 2-minute shower is).

Then I pointed out that the shower has 4 shower heads without flow restrictors (single control) . . . the stop gap was to turn up the HW temperature and have more cold water mixed in -- then my 12-year daughter only uses cold water for fear of scalding when using faucets . . .