To my mind, the Feast of the Epiphany, (the Three Kings), which falls on the 6th of January, is the 'formal' end of Christmas, and I don't have an issue with lights, or decorations, up until then.Finally wrapped up a project I was working on! Now will be moving forward into the new year more smoothly.....
I do wish, though, that people in my neighborhood would realize that, hey, Christmas is long past now, and for that matter, so is New Year's. OK, folks, it's more than time to get rid of the external and internal Christmas lighting and decorations!
The old 'traditional' twelve days of the Christmas feast brought one up to 6th January, and some cultures (such as those of Spain, Orthodox Christians) still celebrate 6th January as a major part of the Christmas festival cycle. Until then, I see no problem; after that, well, Christmas - in the western world, at least - is over.
Now, I do have an issue - a major issue - with such lights and decorations making an (unwelcome) early, indeed, premature, appearance at any time prior to 8th December, but that is a separate matter.