Depending on what kind of race, the tires get worn quickly during the race.
Mechanics change tires during a race to ensure optimal performance. Tires wear out due to high speeds and friction, decreasing traction and handling. By changing tires, teams can maintain grip levels, enabling drivers to drive faster and safer.
I imagine they change tires every stage, because there is no time to do it during race time
A couple of years ago FIA changed the rule that stated a car can change the pneumathics (tires) when in pit stop during the race. Now they can only use the set of tires that they start the race with.
A burn out will ruin tires on race cars by burning up the rubber. The rubber of the tires will get worn from the friction of the pavement causing the tires to tear.
It is nitrogen.
You change tires when they are worn out, not at a set mileage.
Nitrogen
The track and tires are both sprayed with a special solvent compound.
Flat tires is a sign of physical change. The tires go from being normal, to then being flat. This changes their physical form.
slick tyres are used.
Slicks.