That's an opinionated question...my opinion is that you can leave it on and it may be better for it. I try to stay away from sleep mode, as every now and again, it won't come out of sleep mode for whatever reason and I have to reboot by pressing the power button. I look at it this way: The computer parts are like a light bulb...when does a lightbulb blow? When you turn it on. Kind of like "Starting your car is the worst thing you can do".
The down side to leaving it on all the time is that it's constantly sucking up electricity, which means it'll increase your electric bill. On the flip side, you can make programs auto update/download and install in the middle of the night while you're sleeping, like your antivirus, etc. Just don't forget to set your monitor to turn off after being idle for XX amount of minutes (mines set for 20 minutes).
Again, just my humble opinion, I'm sure that others will chime in on this!
War produces veterans, wounded both physically and mentally. They have sacrificed for us.....and it is now our job to help these veterans, as they have already helped us in ways we will never know, in ways that we cannot fathom, and in ways that we take granted every day.