I turn it on only when I need it. I'll say 'bout 5-6 hrs a day on avg. Rest of the time, I save the planet by turning it off & saving electricity
I put it on sleep mode only when I know that I'll be back within an hour or so. But I've disabled the "jiggle mouse" bit. I wake it up only through the Keyboard. As long as the "jiggle mouse" bit was active, every time my mom or I would open the drawers or search for something on the desk, the slightest of vibrations, or even a gust of wind or something would wake the PC up & that would annoy the mess outta me. The space-bar does it for me nowadays.