I’m writing this as someone who has mostly lived in the US and Canada. Personally, I find the whole “lying to children about Christmas” thing just a bit weird (no judgment on those who enjoy this aspect of the holiday). But because it’s completely normalized in our culture, this is something many people have to deal with.
Two questions:
What age does this normally happen? I suppose you want the “magic of Christmas” at younger ages, but it gets embarrassing at a certain point.
And how does it normally happen? Let them find out from others through people at school? Tell them explicitly during a “talk”? Let them figure it out on their own?
In our family it was done like this: The story of how the presents get magically to the house was told, just like you would tell a fairytale, in this kind of storytelling way. Younger children believe it, older children begin suspecting something from the tone of voice. We also let some things slip sometimes, like hiding presents and having to go and buy some secret stuff to help with preparing the Christmas. Children of older preschool age really enjoy being able to find out themselves, suspecting you and catching the clues. Then when they confront you with their theory, you can let them in on the conspiration by just a wink, maybe tell them not to let others know. They then tend to start participating, preparing their own presents for others. It works very well.
I like this. in my family, I figured it out at about 3 or 4, promptly told the 2 year old, and broke the reality to the next two before they could even start to believe there was a real Santa.
instead, Santa was the spirit of Christmas, so any of us could be Santa if we gave presents with no expectation of recognition or a return gift. much more Secret Santa than magical man leaving presents.
this did lead to several years where the youngest would give away all their toys, only to then reclaim them after presents were opened. generosity isn’t an easy concept for the pre-schoolers.