For really young children I think the emphasis should be on having fun and just learning the skills of the game. My daughter started playing soccer at 3 and at that point keeping score is only for the parents.

By about age 6, kids begin to realize their efforts make a difference. And good efforts need to be rewarded. At age 6, kids keep a tally anyway. They know when one team is scoring more than the other.

But when my daughter ends up on a soccer team that isn’t as good as well, any of the ones she plays. even though she’s a decent player. It sucks to see her disappointment when she loses and it’s easier to say to her “hey, it’s just for fun we weren’t keeping score.”