I just received a nice monitor that I hope to keep in use for as long as I can. Should it be turned off every night? It does go into sleep mode when not in use. Are there any settings that I should change to give it a longer life?
There's not a whole lot of difference between sleep mode and turning off, except maybe a couple of watts of power - and I'm not even sure about that, it requires a bit of power to monitor the on/off switch. If you want to ensure being as green as possible turn it off at night, otherwise don't worry about it.
P.S. Make sure the monitor is really sleeping and not just displaying a black screen, there's a huge difference. There should be a light on the panel that will make it evident.
I prefer shutting the devices off if there is no need to let them stay plugged in. I have something like APC surge arrest - extension cable with about 5 outlets and main power switch. I have all my PC components (PC, monitor, speakers and scanner) plugged in and after I shut down computer I also switch the main power switch off. This makes me calm as it 1) reduces the power consumption (why all these gadgets should suck energy when nobody uses them?), it reduces a risk of fire (ok, all the devices should have thermal fuse, but ...) and it has also surge suppressor built in. Also useful in case of some terrible thunderstorm as you can easily drag this main cable out to improve the protection against lightning. So I think there is no reason to keep the devices standby.
PS: as I know, the power supplies do not suffer from often switching on/off but when you let them standby for a very long time, it cuts their life a little bit.
There's no answer to "always leave it on" or "always shut it off".
There's only: "If you are going to not be using your monitor/computer for x hours, shut it off".
What is "x" hours?
No one is ever going to tell you that x = 0.1 hours. (Constantly shutting down every time you walk away from your computer for >6 mins.)
No one is ever going to say that x = 10000. (Leave your computer on, even if you aren't going to use it for WEEKS.)
So, what is x? I say it's around 48 hours. Everyone else will give you other answers.