We used Mousepins in December with zero problems.... not one comment or sneer. As far as the amount of pins, I think that would be impossible to guess. It would depend on if your child is shy or outgoing etc. and would really be mostly limited by how many you are willing to supply. No matter how many we bring each visit, it is never enough. My DD was 7 on our last trip and traded 10-15 pins per day if that helps at all. Pin trading is really one of her favorite parts of each trip and she can't wait until she can get back at it in August.