When it comes to kids I would suggest something maybe a little different, when a kid is starting to get to the point that they are so tired they can't do all they need to to prevent injury on the mat, it is too much, of course there is always a way to correct that, more conditioning. I have found that anything more than about 5 matches a day in serious comp, tends to have a kid get to the place of running into potential harm due to the number of matches, or as I believe, length of time spent at a tournament.