My inside decorations are usually put up by New Year's Day. But with 2 very curious, very active cats - my inside decorating is kept to a minimum and no tree for them to climb!
Outside lights stay up at least till Jan. 6. Then it depends on the weather and how I am feeling. If the weather is good, I will take them down Jan. 6. If the weather is really bad, I will leave them up until I can get out and do it. If it takes too long, I will at least unplug them so they don't come on. I always hate that day - I do love my outside lights and would keep them up and on till spring if I thought I wouldn't start getting really strange looks from the neighbors!