I took my car in for a service yesterday and the dealership found two things wrong with it. The two rear tyres were down to 2mm (the legal limit is 1.6mm) and front and rear brake pads needed replacing.
Now before I too my car to the garage I happened to check the tred depth of all my tyres, and the rears had 4mm, a fact I then made known to the dealership. They then wanted to charge me £180+VAT for fitting front and rear pads. I said no and bought myself a set for £50 and fitted them this morning. And wouldn't you know it, the old pads were pretty worn, but still had several millimetres to go before reaching the wear indicators.
So save yourself some money and double-check what your dealership tells you, and don't be afraid to do some work yourself. Most of it is pretty easy and I saved more than £150 (including the VAT) for a mornings work.