Brake pads are an item that will often need replacing on your vehicle. Depending on how often you drive your car, your driving styles and the type of driving you do will all effect how often you need to replace your pads. For example, a car that is driven a lot of motorway miles that does not involve much breaking may not need to change their tyres as much as someone who has done the same mileage but round town driving.
You may not realise that your brake pads are very low until you take the car for an MOT as often we get used to how our cars drive and may not realise that it is taking longer to stop. You may also discover a squealing sound or grinding sound when you apply the brakes. This is because your pads have a noise warning on them which will make these sounds when the pad wears down to that level. At this level you need to change your pads as soon as possible. If you have been driving with worn pads for a while you may find that you also need to change your brake discs too.