Should you invite the entire class to your kids birthday?

For several years, birthday parties in our house were gigantic — most, if not all of the birthday child’s class were invited and my attempts to impose some kind of cap on the number of invitations or the duration of the knees-up were inevitably voted down by the rest of the family.
On any given birthday we could have anything between 25 and 30 children engaged in the games and events we organised to keep them going for the entire afternoon.