@comicsgate great information there.
There are also variances in the West. For some the religious aspect of the season extends well beyond Christmas Day. As part of Advent, the 12th Day of Christmas, Feast of the Epiphany lands on January 6 each year.
As for the decorations/superstition thing…I usually take my decorations down on January 15th.
Twelfth Night (holiday)
Date: 5 or 6 January
Twelfth Night (also known as Epiphany Eve depending upon the tradition) is a Christian festival on the last night of the Twelve Days of Christmas, marking the coming of the Epiphany.[1] Different traditions mark the date of Twelfth Night as either 5 January or 6 January, depending on whether the counting begins on Christmas Day or 26 December January 6 is celebrated as the feast of Epiphany, which begins the Epiphanytide season.
A superstition in some English-speaking countries suggests it is unlucky to leave Christmas decorations hanging after Twelfth Night, a tradition also variously attached to Candlemas (which marks the end of Epiphanytide on 2 February), as well as Good Friday, Shrove Tuesday, and Septuagesima. Other popular customs include eating king cake, singing Christmas carols, chalking the door, having one’s house blessed, merrymaking, and attending church services.
https://en.wikipedia.org/wiki/Twelfth_Night_(holiday)#In_literature