Smart lights can help you save energy, and also keep your house more secure. If you've got your lights automatically coming on at sunset, then you should also set up a routine to make sure they turn off later on at night. Not only does this save energy, but lights left on all night for more than one night is a clear sign that the house is unoccupied. The simplest way to do this is to set a regular routine that turns off all lights at a particular time at night. If you have sensors in your smart home network, you can also use them for a more sophisticated solution.
To do this in Alexa, create a new routine, and in the "When" section, you can choose a specific time. You can then add the action to turn off all your lights.
In the Smart Life app, in the "Smart" menu, choose "Automation", and add a new routine with the blue cross. Select "Schedule", and you can choose the time, and the set the action to turn off all your lights.