Setting random Colour + Destroying objects

RandomColour.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class RandomColour : MonoBehaviour
{

    public int randomValue;
    public float randomTimerValue;
    public float randomDestoyValue;

    public float randomXpos;
    public float randomYpos;

    public Color colour1, colour2, colour3;
    float timer;
    float maxTimer = 0.1f;//half a second

    private void Start()
    {

        randomXpos = Random.Range(-5f, 5f);
        randomYpos = Random.Range(-5f, 5f);

        transform.position = new Vector3(randomXpos, randomYpos, 0);


        randomTimerValue = Random.Range(0.1f, 1f);


       
        randomDestoyValue = Random.Range(1f, 5f);
        Destroy(gameObject, randomDestoyValue);
    }


    void Update()
    {
        ChangeColourOnTime(randomTimerValue);
    }


    public void ChangeColourOnTime(float _seconds)
    {


        timer += Time.deltaTime;
        if (timer > _seconds)
        {

            randomValue = Random.Range(0, 3);
            if (randomValue == 0)
            {
                GetComponent<MeshRenderer>().material.color = colour1;
            }
            if (randomValue == 1)
            {
                GetComponent<MeshRenderer>().material.color = colour2;
            }
            if (randomValue == 2)
            {
                GetComponent<MeshRenderer>().material.color = colour3;
            }
            timer = 0f;
        }


    }


}