Do you have any preference between double posting and using the edit option?

I've noticed people double posting for simple things, so I assumed it's okay. But I'm just wondering which you would really want us to do. Edit previous posts, or double post...?

Editing previous posts would be preferred, because double posting just takes up extra space, and at times, that second post would end up looking sort of ratty and insignificant. So if you can, edit the post - if you ABSOLUTELY HAVE TO, you can double-post.

Whee! Knowledge is power, thanks.