What is the ofsted schedule for outstanding schools?

[temporary]

Our school was last inspected in 2008, graded as outstanding. I am wondering when the next inspection is due, as someone said to me that an inspection will only be triggered by a complaint....which sounds weird to me. Surely that means the school could go a very long time, with changes of head and a drop in results before it is next tested.

I think a drop in results can also trigger an inspection.

DCs secondary hasn't been inspected since 2006 and has changed to become an academy. I think although the results are steady, they are still expecting an inspection anytime soon.