I have always answered such questions this way: pick how you want to kill it.
Every electronic device and component is expected to last a particular amount of time (usually rated in hours).
When you turn on an electronic device, you cause it to be under stress until it stabilizes. That stress takes a little bit of life away from the device.
So, I tell people that they can either leave a device on, and reach it's rated number of hours faster.
Or.. they can turn it off and reach that number of hours slower, but stress the device each time they turn it on and essentially shock it to life.
Essentially... pick which way you want to kill it. Either run it out of time, or shock it until it dies. Either method will kill it. You just pick how you want to get there.
Let's look at a lightbulb. Just for illustration, let's say it's rated for 800 hours. That's approximately 33.3 days if you leave it on 24 hours a day.
So, if you never turn off the light, you can expect that in approximately one month, you'll need to replace the bulb.
Now let's say you're only home 3 hours a day. Now that same lightbulb should last you approximately 267 day if you only turn it on when you're home.
But... each time you turn it on, you stress it more than if it were left on. So, just for illustration, we'll guess that the lightbulb might actually only survive 160 days (due to both stress and it's useful life working against it).
And, most likely, its death will be during a moment of stress.
So... which one killed it? Stress??? Being left on??? Actually both contributed.
But, by turning it off when it wasn't being used, you did get more personal use out of it. You also made that $1 lightbulb last longer (saving money). And... you saved electricity (also saving money).
That said... I could theoretically kill a new lightbulb in an hour or two (probably less) if I constantly flipped the switch off and on nonstop until I stressed it to death (though some bulbs are obviously made to handle that stress... for example light shows, etc.)
So, hopefully that gives you a better idea of the equation in front of you.
However, what you describe is not the same as powering the system off and back on. Leaving the computer on, and rebooting it is more similar to never turning it off, and periodically using it, and periodically entering low power mode and waking it up.
You haven't described actually shutting it down and stopping the flow of electricity through the many component parts.