You have a really low AP build, I bet something besides lich bane would be way more efficient for you. Just a suggestion.
An hourglass is probably more efficient, but I haven't really felt the need for it. The lichbane gives a decent kick every 1.5 seconds. I think I end up with about 170 ap. The games have, in all honesty, been over by that point anyway. I've been thinking about getting a black cleaver or something instead. Might as well shred even more armor.