This discussion has been going on for at least 15 years with no real consensus. About 50% leave their systems on 24/7 and the remaining 50% switch their systems off at least once a day.

I fall in to the latter group. I boot-up in the morning and shut down when I hit the sack. My one exception would be a humongous thunder and lightning passing overhead ... I pay heed to those and shut down right away.

So, the answer is do what you feel comfortable with as in the long run it doesn't make much difference and is really not worth debating.