So December 1 is the day everyone puts up their Christmas tree, right? It's tradition. It is bad luck on your house if your tree is already up.

Actually, no, there is no real rule except the rule you grew up with.

Monash University Professor Gary Bouma, sociologist on religious diversity, says families and individuals abide by the traditions of Christmas that they grew up with as a child at home.

"It really is what you grew up with, but for some of us it is also when you have the time to throw the thing up," Professor Bouma said.

He said the tradition of not putting up a tree before December 1 is a strong one in Australia but not for all.

Many Christians will only put up decorations on the night before Christmas Eve and never during Advent, the period that includes the four Sundays before Christmas Day.

"Traditionally, for many Christians, Advent is a time of fasting - none of this extra food that we do normally in Australia - and you can't sing Christmas carols," Professor Bouma said.

"But in Australia I've noticed that the partying starts about now," he said.

He said the tree was essentially illegal in Britain or unknown, until Prince Albert, a German, brought it to the masses and periodicals, like the Illustrated London News began describing the royal tree in intricate detail.

"Christmas was illegal from the time of Cromwell to mid 19th, Scrooge was normal," Professor Bouma said.

At the White House, President Barak Obama and First Lady Michelle Obama will "flip the switch" on December 3, no doubt giving everyone the right to do the same.

So when should the tree that takes up a lot of space in your lounge room come down?

For some, the tree must come down by January 6 - or the Epiphany when the three kings are said to have arrived. What exactly happens if you don't isn't clear with some saying hobgoblins will come to wreck your house for a year if you don't.

"There is large tradition of Christmas trees coming down by the Epiphany, but that is not true in France. In France, it starts a month of celebrations and eating," he said.

The Epiphany heralds the arrival of the gallette de rois - the cake of kings - a pastry and marzipan affair baked in rings.

Professor Bouma said the tradition of pulling down trees in Australia by January 6 might be because of the warmer climate. He said in Europe and America the trees would often stay up well after Christmas until they dried out and became a fire hazard. He said those trees were heavily hydrated compared to Australian fresh Christmas trees, which grew under drier conditions.

"They are bad enough when they are new and full of juice but they dry out and become tinderbox," he said.

Professor Bouma said the good thing about the dispute about when Christmas trees should go up or come down made for lively conversations.

​"I don't want to complain about Christmas tradition crossing civilisations. People will have disputes about local variations and this enriches conversations and traditions that families find terribly important," Professor Bouma said.