Would be interested to know what shoes you routinely buy for your 13-year-old DS (eg school shoes, football boots etc) and what you would regard as an "extra" that would either be a birthday/Christmas present or be paid for out of your DS's birthday money. If the answer is that you give your DS a clothing allowance per month, how much do you give? Does the allowance have to cover absolutely everything (eg school uniform, clothes that are needed rather than just wanted) or are there some things you pay for outside of the allowance?
Interested to hear what others do!