I've been in the habit of opening my oven door before pre-heating for about eight years now. Just to make sure. Because you never know.
Why do I do this, you ask? See if you can figure it out. I'll give you a few clues:
1. Bethie was about three when I started.
2. She liked to play "kitchen."
3. With her cousin.
4. This often involved using the (cold) oven to bake pretend muffins.
5. Using real muffin tins.
5. Filled with small plastic shapes.
Are you in the habit of checking your oven? If you have a small child, maybe you should be.