When to hang decorations for halloween

When is it the right time to start hanging Halloween stuff. I have a neighbor that put out their tacky crap almost a month ago. When is it too soon to hang your seasonal stuff? How do I get out of candy-giving on Halloween?

To get out of candy giving, just lock your doors and turn off the lights.

If you don;t want the subterfuge, then just put up a 'we hate halloween' sign in a well ligted area next to your door.