i haven't routinely "powered down" a desktop in years (and years), and restart mine rarely enough that I couldn't really tell you for sure, but on average, a-few-to-several times per month: for software updates that demand it, when something flaky, but not serious enough to research and "really" fix, happens and I know from experience that rebooting will take care of the problem (like when the Gigabyte utility that remaps my mouse keys occasionally goes haywire for no apparent reason), or once in a while, on whim, just to kind of give it a relatively clean slate.
Thanks to a smartphone and a tablet, I don't use a laptop much these days, but in general, I've always been more likely to turn those off completely than desktops. I know hibernating them should basiclly be the moral equivalent of powering them down, but somehow it just "feels" like turning them off completely is more likely to extend their generally-less-robust lifespans, even if only a little...
Thanks to a smartphone and a tablet, I don't use a laptop much these days, but in general, I've always been more likely to turn those off completely than desktops. I know hibernating them should basiclly be the moral equivalent of powering them down, but somehow it just "feels" like turning them off completely is more likely to extend their generally-less-robust lifespans, even if only a little...