Different procedures at different airlines; also some airports have their own requirements. For example flying into Narita-Tokyo when coming from Anchorage we are supposed to drop the gear pretty early, prior to reaching the shore line.

This, I think, is to prevent ice chunks falling off the gear onto houses in the neighborhood... We’re especially protecting that one dude who has a “Down with Narita Airport” banner hanging from his fence…

Also, some airlines save lots of fuel by keeping the gear up all the way to the ground. I think it's called cost index "ground neutral".

http://media.myfoxboston.com/images/...irlines500.jpg