Zephyr, who uses it?

Boots replacement for adcs.

Irelia if stupidly fed in lane

most ADCs, hecarim, udyr occasionally, not much else

When your crushing the opponent and one item would have no significant impact on winning/losing team fights or the game because victory has already been secure. Semi-srs Kappa.

I use it on Hecarim. It gives him a nice speed boost and adds Tenacity, which lets you take instead of . I know Udyr players tend to use it, but not many other champs.