A month ago, I stumbled into a very clever invention, the gas water heater timer. A patented device that enables you to electrically control the valve on the front of your water heater. (You can also adjust the temp setting of the water heater, but not remotely) The average person goes to bed around 11 or so and wakes up at 7 or so. so for around 7 hours, there is no need to heat the water in your tank. Have the water heater turn on at around 6 am and by 7 you will be all set. A gas water heater can recover temperature quickly, so you should only need around 1-2 hours to make the tank a comfy shower temp, and if you shower at night, and leave early in the morn... there is really no need to turn it on till 1-2 hrs prior of your returning home from work.
When the switch is off, the water heater valve is rotated to the vacation position, then when turned on - back to the preset temperature. It comes with a manual timer switch, but that is a throwaway in this day and age.
With a wifi enabled plug, scheduling and bypassing schedules and also vacation control become trivial. Tie it into the away/eco setting on your Nest thermostat and really get carried away. This device is a dream for second homes or vacation properties. Embrace home automation and save money and the environment. There are 3 different models available depending on your water heater type, but you indicate that during the ordering process. All the newer water heaters use the type 3 design, as pictured above. Choose the gas valve from the picture below, a wifi plug of your choice, and you will be all set. It only took around 5 minutes to set it up, including the smart plug programming.