Many tyre shops and manufacturers offer tyres with xx,000 kilometre guarantees.
Don't be taken in by this. It is a stretch to believe in a guarantee on a consumable product that the life of which is entyrely dependent on the suspension geometry of the car it is being used on, the style of driving, the types of road and the weather.
There will typically be a long list of what isn't covered also, including:
Road hazard injury (e.g. a cut, bubble or puncture), incorrect mounting of the tyre, tyre/wheel imbalance, improper repair, misapplication, improper maintenance, racing, underinflation, overinflation or other abuse, uneven or rapid wear which is caused by mechanical irregularity in the vehicle such as wheel misalignment, accident, fire, chemical corrosion, tyre alteration, or vandalism, ozone or exposure to weather.
Given that you really can't prove any of this, the guarantee is therefore worthless because it is left wide open to interpretation by the shop/manufacturer.
The xx,0000 kilometre guarantee is merely a sales ploy. No one, not even the manufacturers, can guarantee that their tyre won't incur damage the moment you leave the shop.
Buy your tyres based on reviews, previous experience and the recommendation of others. Do not buy one simply because of the guarantee!