the second characteristic is the age of people. this is useful when seeing whether any discounts are available for the person or even whether they are allowed to book. for example, a wine tasting course could offer discount to OAP's. on the other hand someone under the age of 18 is not allowed to drink and will not be allowed to book.
the third characteristic is the date on which they wish to book. this is important because obviously these days cant fall on bank holidays or when the business is closed. this also has an effect to what will be running on these days. for example a snowboarding course in france may only run during the winter period so therefore applicants wouldnt be allowed to book in august. another example would be no snowboarding during christmas week.