When the tread is worn down, tires lose traction during braking and won't grip the road well when driving in the rain, ice and snow. But even if there's plenty of tread left, tires should be replaced if they're too old, at least every six years.

How do you know when tyres need changing?

Small bars of rubber running across the grooves in between the tread – called tread wear indicators – tell you when the tyre is worn out. If the tread is worn down to these bars on any part of the tyre, it's worn out, unroadworthy, and needs to be replaced.

How long before you should change tires?

It may be tentative, but tires do have an expiration date. There is a general consensus that most tires should be inspected, if not replaced, at about six years and should be absolutely be swapped out after 10 years, regardless of how much tread they have left.