As kids grow up, there are good chances they’ll ask you this question, for instance because an older cousin tells them they’re stupid because they still believe in Santa’s existence. That’s the case of Jameson for instance, who wrote an amazing letter to Auntie Rita (today on Timbuktu), providing several proofs that Santa is real.
What do you tell your kids? The way I see it there are two cases, and it’s important to understand where the question is coming from to give the best possible answer for your kid’s particular development stage:
1) Your kids badly want to believe that Santa exists, but they’ve been told by someone that Santa doesn’t exist.
In this case, do not hesitate to reassure them. They still want to believe, they still need to believe, and there’s no reason why you should tell them Santa isn’t real. You can play a small game to show them Santa’s existence, like leaving buying a bunch of carrots for Rudolph (that MUST disappear on the following morning) or playing bells in another room on Christmas Eve while they’re in bed, to pretend Santa’s sled is passing by in that very moment.
2) Your kids know Santa isn’t real, and want to check with you if they’re allowed to be open with you about their doubts.
Face the moment. It’s going to be tough, and your kids will probably be angry and sad for a bit. It’s completely understandable: after all, Santa is a very important belief in childhood, and adds a little magic to everything. Deal with their disappointment and explain you can recreate the same magic together, and that Santa represents the Christmas spirit: the Christmas Spirit doesn’t disappear with Santa, and actually it becomes grown-ups’ responsibility to keep it alive. To do so, you can do something together, for instance, or create together a new tradition: find some sample activities here!