Set up a Christmas tree or decorate with Christmas-specific trimmings on Black Friday, the day following Thanksgiving. Your lovely tree won't overshadow your huge turkey meal if you wait until Black Friday.
You can decorate earlier with neutral Christmas palettes that work for both seasons. Red, reindeer, and Santa Claus decorations should wait until after Thanksgiving.
It is recommended that you wait until the very last possible moment, which is Christmas Eve, to decorate your Christmas tree if you find that holiday decorating causes you more worry than delight.
Getting your house ready for Santa Claus the night before the big day should become a custom that your family participates in.
For individuals who don't fit into either of those categories, you can put up decorations on December 1 and take them down the day after Christmas.
Putting up an artificial tree is the easiest way to maintain Christmas decorations. If your attic is big enough, you can store it decorated.