I think I was 7 or 8. I reminded my parents to remove the AAFES price tags before they filled the stockings one Christmas Eve. There was a pause while they looked around, saw I had chosen a moment when my brother and sister weren't around, and they simply said, "don't ruin anything for your brother and sister."

They never actually admitted there was no Santa until about 25 years later when we were holding Christmas at my house and my dad said humorously that he wished we "kids" would go to sleep so they could fill the stockings and I told him it was my house, I was filling the stockings! Come to think of it, he never did come right out and say "there is no Santa," even then.