Problem Checking A List

Well...it seems I'm re-approaching this problem. What I'm experiencing is...uhm...I guess you could say when I "despawn" a monster (the player has killed it), and "respawn" it...it adds all the moves to the list all over again. For example:

Monster A has 2 moves in his list: Scratch & Growl... Monster A dies... Monster A respawns... Monster A now has 4 moves in his list: Scratch & Growl...AND...Scratch & Growl...

Here's my code:

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
  
 public class MonsterMoves : MonoBehaviour {
  
     public List<BaseMove> moves;
     public int level;
     public Scratch scratch = new Scratch();
     public Growl growl = new Growl();
     public FireBall fireball = new FireBall();
     public PowerUp powerup = new PowerUp();
  
     void Start(){
         moves = gameObject.GetComponent<Monster>().monstersMoves;
         level = gameObject.GetComponent<Monster>().level;
     }
  
     void Update(){
         level = gameObject.GetComponent<Monster>().level;
         SetupMoves(level);
     }
  
     private void SetupMoves(int level){
         if(level >= 1 && !moves.Contains(scratch)){
             moves.Add(scratch);
         }
         if(level >= 1 && !moves.Contains(growl)){
             moves.Add(growl);
         }
         if(level >= 7 && !moves.Contains(fireball)){
             moves.Add(fireball);
         }
         if(level >= 10 && !moves.Contains(powerup)){
             moves.Add(powerup);
         }

Any ideas on what I'm over-looking?

SO I'VE MADE SOME CHANGES. Now I call the function whenever the monster is first created, and if/when it levels up. Here's the new script for the MonsterMoves...

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 
 [System.Serializable]
 public class Moves : MonoBehaviour {
 
 public List<Move> moves;
 public List<Move> movesToLearn = new List<Move>();
 
 void Start(){
     moves = gameObject.GetComponent<Monster>().monstersMoves;
 }
 
 public void AddMoves(int level, List<Move> moves){
     foreach(Move move in movesToLearn){
         if(level >= move.levelLearned){
             if(!moves.Contains(move)){
                 moves.Add(move);
             }
         }
     }
 }
 }

I call this function in the script that handles all of the properties of the monster. If the list of Moves already has the move in it, I don't want to add it again. However, it's still not working properly. It's STILL adding the move to the list, even if it's already in there.