For "short haul", that is flights of 50 miles or less, normally I fly 2000' to 3000'. For longer cross-country usually 4000' to 5000', only going higher if I want to avoid cloud surfing.
I have been up to 10000' a couple of times, just to say "Done that" and to enjoy the view. But to be honest, in anything I've flown, it's a bit of a struggle and not normally worth the time crawling up those last couple of thousand at 200ft per minute or less!
As far as engine-out glide is concerned, I suspect 10000' is a little bit too much time to overthink the situation!