Saving electricity is good and right, but not useful for every electrical device. Modern televisions, for example, should be permanently connected to the power grid. Also, when not to pull the plug.
The approach of completely disconnecting devices from the mains so that they do not consume energy unnecessarily in standby is spot on. The easiest way to do this is with switchable plug strips. But not every device may be disconnected from the network.
If this is the case with a device, the manufacturers usually point this out in the operating instructions. Modern OLED televisions, for example, should remain connected so that they can regenerate the display at night.
In principle, it does not damage the WLAN router if you disconnect it from the network night after night. However, it is not absolutely necessary and can also have unpleasant side effects.
Nowadays, landline telephones are usually also connected via the router. If the device is connected to the network, you cannot be called during this time. Turning off the Wi-Fi signal at night helps to save electricity. With many routers, this can be done with a simple push of a button on the device. It is often possible to set the router menu so that the WLAN module is switched off automatically at night and switched on again in the morning. Here you can find out what saves electricity with the router – and what not.
Another example is inkjet printers. With them, too, it makes no sense to unplug them after each use. Because the printers start a print head cleaning run every time they are disconnected from the mains and then switched on again. This uses a lot of ink. And that is mostly more expensive than the electricity saved.