My 7 year old still believes in both the Tooth Fairy and Santa. 

My 10 year old doesn't believe in either of them. She was very disappointed to learn about the "truth." More so for the Tooth Fairy, I think.

I think that most kids learn the "truth" from other children. I did. That's just the way it goes.

My six year old does still believe in the Tooth Fairy and Santa Claus.  My 10-year old doesn't.  He was beginning to always question were they real - and I finally told him that I was the Tooth Fairy and Santa Claus.  I told him that he couldn't tell his sister...and he was quite tickled to have a secret from her. 

My kids believed in the Tooth Fairy until she/he kept forgetting to visit for days on end. I told them that lots of kids were losing teeth & the poor Fairy must  be overwhelmed. They didn't buy it.  But they kept putting their teeth under their pillows and expecting some moola. Silly kids.

(That's just my older three, I have one last young one who hasn't lost any teeth yet-so there's still some magic left.)

Santa-same thing, but he always remembers to visit. (I tell them what my mother told me, "When you stop believing in Santa-he stops bringing the gifts."--funny take on this one-My first Christmas away from home, I walked to the living area expecting & hoping to find that he'd visited. It was a very sad growing up experience for a 21 year old .)

ok- have to elaborate-I left home before I was 21. That was just the first Christmas I was away from my family.