SimpleMonitorOff

If you are like most users, then there is a good chance that you lock your computer whenever you are away from keyboard for several minutes. Generally speaking, locking your computer means that you have no intention of using it for a while, case in which you may also want to save a few cash and power off the monitor as well.
SimpleMonitorOff is a lightweight utility that automatically switches off your monitor when you lock the computer and hence, could help you extend its lifespan.

Simply install and forget about it

It is worth mentioning that unlike similar tool, the program does not come with an interface. Consequentially, you cannot add hotkeys, shortcuts, click or configure anything, as it reacts to the Windows events only. Simply put, when you lock your computer, it powers off the monitor, regardless of the hotkey combination you use.
As you probably already hinted, as soon as you access the mouse or keyboard, the monitor is going to wake again so that you can enter your PIN or password to unlock your computer. It does not have any special requirements, even though the developer recommends that you use an account with local administrator privileges for the installation.

A handy utility that can help increase the monitor's lifespan

Granted, it can be argued that Windows does eventually power off the monitor by itself after a specific interval. In fact, you can easily configure the idle period from the Windows Control Panel. However, by default Windows does not turn it off as soon as you lock the computer and hence, the utility of this tiny tool.
In spite of the fact that it would be useful for the app to have some options so you can customize the behavior better, SimpleMonitorOff can come in handy for anyone who would like to turn off the monitor when locking the PC automatically. Not only does this help increase the device's lifespan, but it can also help you save the environment and some money at the same time.