At what age do parents break it to their kids that there IS no Santa Claus?

I'm a kid, my parents, never told me about Santa. My mother used to believe Santa was real until she saw him taking off his beard in his dressing room. I would never lie to my children for years about something that doesn't exist. Do you know how much trust that breaks? You can lose trust over things like this! I have a friend to this day believes that Santa exist, and he will not play with dolls, though he doesn't think Santa is nearly as "un-manly" as dolls are. If you don't tell them, the kids will find out themselves, and it will not be a very happy revelation. If you tell them now, you can work out the trust you have lost. My dad, grew up in a poor family, all his schoolmates believed in Santa, but he didn't because he never got any presents for Christmas. Don't destroy your children's trust with this character!