How can I add a number only once, and not continually?

Firstly, you can create method Hit() where you add points to general score. You can call it on Collider.OnCollisionEnter.

Secondly, you can create a data class which would represent a ball type. I see that you have balls of different colours. You can do:

public enum BallColor{ Red, Green } [Serializable] public class BallData{ public BallColor color, public int points }

And in your MonoBehavior class you can do:

[SerializeField] private List<BallData> ballsConfig;

Later you can access this data like this

var score = ballsConfig[0].score; var greenScore = ballsConfig.Find(ball => ball.color == BallColor.Green).score;

I'm not sure how your code works. It's not clear from the snippet you shared. Maybe I can help if you provide more info.