On Mon, 29 Dec 2008 22:51:32 -0600, Dan wrote:

If my electric water heater is not providing adequate hot water for a 20
minute shower anymore is it time for total replacement or just replacing
the thermostat? TIA, Dan

How hot is the water it does provide? I don't know if thermostats
change their effective setting, but if they do and if water isn't hot
enough, making it hotter will make it last longer.