My 7D has (I estimate) between 15k to 20k shutter actuations on it and the shutter failed three weeks ago towards the end of a day's shooting.One moment it was producing pictures and seconds later up pops ERR 30. I've had it for a bit over two years so it is now well outside warranty.
Today I took it into Canon at Elstree (UK) for repair so it will be interesting to hear what they say. A loose screw, if that's all it is, does not sound like an expensive repair, but I did note a labour estimate of £120 listed on the wall, with parts on top, for a faulty shutter. Since the "mileage" is so low, if not the age, and I have CPS Gold membership, I did ask them to consider throwing in a bit of goodwill on the repair costs. I'll be expecting a call early next week to let me know the prognosis.