How often should i change my car tyres?

i bought a peugeot (new) in november 06 and wondered how often the tyres should be changed? and are they under warantee?How often should i change my car tyres?Tires are a wear item, so they are not covered under any warrantee. Generally tires will last about 60,000-75,000 miles depending on the type. Make sure you rotate the tires.
How often should i change my car tyres?
You should get new tires when the tread is wearing down.