What's With The Push To Vote Early???

There has been a constant cacophony from both sides of the aisle to vote early. Why?

Are candidates afraid of negative news that might come to light just before the traditional voting day, consequently ruining their chances of winning?

If that's the case and my guess is,  it is. Why would anyone do so?

Why not wait till November 8th when you've got as much information on the candidates as possible?

I just don't get it, unless you're going to be out of town. But then again, absentee ballots have been available forever. Any guesses out there?