Depending on situation, to disable the router can be useful or, conversely, counterproductive measure.

Saving electricity

If you care about saving electricity, it makes sense to turn off the router at night to eat. When the computer is not included and you do not use the Internet, the router will continue to consume electricity. If router just disable, without removing the plug from the socket, it will still consume electricity. Then, after a certain time the consumed quantity of energy can be much larger.
Wi-fi routers are made with the expectation of continuous work and frequent disconnection can reduce their lifetime.

The router is dual-purpose

In some cases, the router can simultaneously serve two purposes. For example, the device can be connected to a desktop computer, and the last would be to distribute the wireless signal. If you have installed this wireless network, when you disconnect the router the whole system will also be disabled. It is associated with certain inconveniences.

If you regularly connect to wi-fi using a smartphone or tablet computer, disconnect the router will be harmful.

The problems associated with the router

From time to time router you need to reset and unplug. If the router is not connected to the Internet, then disconnect and reboot. But for the correct operation of the router it does not need to turn off every night. On the contrary, his regular disconnection can lead to difficulties in connecting to the global network. Sometimes a router is unable to detect the IP address or not may be included, if it is too often disconnected.
In some cases, because of the constant disconnection decreases the speed of the Internet connection.

If you have no home wi-fi network, and you plan to be away from the computer for a long time, turn off the router makes sense.

There is some danger if you left the computer and the router, and leave. In this case, it is likely that the computer will be infected, or the crooks can produce its breaking through the world wide web. So when you're not using your computer, disconnect from the Internet.

If you are working at the computer and not go online all day long, and the router is also not needed and can be disabled. In other cases, it is not necessary to turn off the router, even if you turn off the computer and other peripheral devices in order to save power.