Hello and thanks for your answer.

The desktop is switched on all the time. I work on it in the evenings. My wife uses is occasionally. The rest of the time it's on its own. So .. what this gives is .. I don't know :)

I can safely say that it is mining most of the time. After all, you can't squeeze 100% out of your CPU and GPU if you are not playing graphical games or doing some graphical design...

Even when the miner is working in the background it is not interfering with the human work. And you can always switch it off or set in manual mode.