Sometimes devices and power adapters can use electricity even though they are turned off. A remote control, such as a TV, must constantly listen for the “on” command.
A quick rule of thumb is to feel the device once it’s been turned off for a while. Do you feel it is warm to the touch? If it’s warm to the touch, it’s probably wasting electricity.
You need to decide how concerned you are about the electricity consumed. The power that devices use when they are off is usually very low. A good charger for your phone will only use milliwatts per year, which could cost you just one cent. It is not worth it to plug and unplug your phone all the time. Instead, you can spend your time looking for loose change on the couch cushions.
However, it is worth switching the switch to stop the power drain if there are large devices connected to the power strip. I have my TV, Xbox, Blu-Ray player and cable box all on one power strip. I have used a Kill A-Watt ( kill a-watt Google Search
To measure the power draw for the entire entertainment system, use the following: It draws about 300 watts during use and 30 when it is off. The cable box, which maintains a data connection to keep TV guide current, is probably the most dangerous. My annual power savings will be $30/year if I use the power strip to turn off the entertainment system 20 hours per day.
My air conditioner in Houston, Texas, consumes about $1000 annually. It doesn’t do much to turn off gadgets compared with reducing your usage of the big hitters, cooling, heating, washing, etc.