For me the problem with wing stamps is if a non fancier gets the bird they will never think to open the wing and look for contact details. I have used telephone number rings this year, I had one reported out of about 6 lost. So for me, the cost/hassle of getting/putting on the telephone rings was worth it. First year racing next year, the only thing that puts me off the phone number rings is if it slows down getting the rubber off if they put it over it or above it.