I am getting ready to build a 6' tall 80' long wooden fence, but instead of 4x4 wooden posts I am going to use metal fence posts. The fence will have 1 walk through gate and a larger gate that can be driven through. It will be attached to another fence on either side (one is sturdy, and another well is not so sturdy and I will probably replace it within a year). I think I remember reading before that I should put gravel at the bottom of the hole of each post to allow water to drain from the post.
I want to make sure the new fence I put up is done right, and that it will hold over time. So how deep should I set the metal posts, and if I should put gravel at the bottom of the hole, how much?