I love fall, so therefore I decorate. I put up decorations the first part of Sep and they stay up til after Thanksgiving when it's time for Christmas which I leave up all winter. I don't put up a big tree anymore, so the decor doesn't look so Christmasy for winter.
I have two of Valerie's 3' snow covered, lighted "droopy" trees (can't think of what they're called) and they look very winterish that I keep up all winter. And all my lanterns, finials, etc.
Then I decorate for Easter, spring and summer and the whole thing starts all over again 
I also decorate my front door for the seasons with a red, white, blue theme from Memorial day thru 9/11. And of course my flag flies year round.