I always turn everything off when I'm not using it, and every night. And I physically took out the USB WiFi card and folded it up and put it away so it is quite impossible for it to make any contact with Steam (or anyone else for that matter). I have two gaming rigs (long story but now find it convenient) and a very, very nice "gaming" laptop that my family got for me. So even though one of the gaming rigs is experiencing motherboard/technical issues, and the other one I have physically removed the WiFi card, with my laptop (and a tablet, also have an android tablet) I have plenty of options to surf the tubes. My phone and internet bill are now over $100 a month, and the time may/will likely come when I can no longer do that, and so I'm testing whether I can play games I BOUGHT AND OWN after that day comes, so I physically removed that rig from the internet for the test, just as it would be if I cancelled internet (which accounts for well over 60% of that more than $100 monthly bill).

A note about "sleep mode."

I have twice now, and I know I have no idea if they're connected and it was years ago so even if they were connected they may be better made now, but twice I lost monitors that I would routinely let "go to sleep" when not it use. Both had the almost exact same symptoms, as one day after being asleep they would no longer wake up. And so I was convinced the sleep mode was in some way "harmful" to the whole monitor getting power thing. I don't know how, it just seemed like both monitors could no longer get power and I was convinced it had something to do with the sleep mode shortening the life of the power supply, or something. I mean it's obvious there is some connection, as that's what sleep mode does, it blocks, or cuts off, power. Then one day power was blocked permanently. So ever since then I've been anal on always turning everything off. Monitors, TV's, laptops, my tablet, everything. LOL, may not have had anything whatsoever to do with sleep mode, but they were two of the first ones that I had ever had with it, so I was convinced it was connected. At the very least it's made me develop good habits about turning everything off everyday, which has to save on my electric bill.