Many customers may not realise, that track day use is actually more strenuous on the engine, transmission & brakes than almost any other form of motorsport. The closest form of motorsport to track day use is actually endurance racing. I will give you a few examples.
If you were to sprint or hill climb the car, you would warm the engine in the paddock to the correct engine & water temperatures, then the engine would be driven under load for anything between 20 seconds to a maximum of 4 minutes. This may be carried out between 4 and 8 times a day and I am sure if you do the sums, you will work out that this is not a lot of running. Apart from the time involved running the engine, the major stress on a sprint or hillclimb car, is the heat cycles it goes through.
When racing a car, at most club level motorsport, it would consist of between 5 and 20 laps of practice and maybe a 10 - 20 lap race. Most of which would be less than 20 minutes of running. Obviously, more stressful than sprinting or hill climbing from its sustained use, but less stressful from the heat cycles.
Then we come to track day use. We have many customers who inform us they use their car for road use and probably a track day once a month. Typical usage during a track day; you turn up in the morning, do noise check, then out onto the circuit, drive the car around until you fancy having a cup of coffee. It could be 20 - 50 laps with no let up. You have your cup of coffee, maybe even let your friend go out and do another 20 laps, he brings the car in just long enough for you to change over, then hammer around the track until lunch time. After lunch a repeat of the morning.
The track day is comparable with 100+ mile races, maybe even getting closer to a whole club level season in one day. This is often with a car that has not had sufficient modifications to cope with this kind of treatment. An endurance car would have bigger brakes, larger cooling ducts, special tyres, oil coolers and many other up-rated components to cope with the rigors of this kind of use.
So when you intend on using your car for track days, try to remember how much stress a track day puts through a car. Try to make your car as ready as possible, giving it full overhaul before and after the event. Pay particular attention to the parts, bearing in mind that they have the equivalent use in one track day as one years road use, therefore may need replacing after each track day. You must expect your car to require more maintenance than a car used for sprinting, hill climbing or even normal racing.