I've only played 2 characters past normal, and haven't imbued anything. Of those two, my necro hasn't deeded yet, so I'll save the next white bone wand or head that drops and try imbue on it.
I want to, but whenever I actually get to it I go "but it'll get a horrible roll I should probably use it on something more important later on" and then forget about it... until next time I think about imbuing something. I should probably use it on circlets as those are most likely to not suck since weapons can be imbued by lvl8 chars if qlvl is high enough.
I do imbue on a lvl8 character though anything that is high enough qlvl to be good with such an imbue (generally qlvl>=78 but for gloves/boots doesn't need to be as high - then again gloves/boots aren't really worth the trouble, it's mostly to get an awesome rare elite weapon).