Problem with waitforsecond and IEnumerator

Questions & Answers
1

Hi. I’m trying to place a block ever 0.15 second when i,M holding mouse button down. it Works perfectly. However, when i try to do the same thing to destroy them (every 0.3 second) it waits 0.3 second, then destroy one every frame. How can i fix this ?

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

public class placeBlock : MonoBehaviour
{
   
	public GameObject cube;
	public Collider up;
	public Collider bottom;
	public Collider right;
	public Collider left;
	public Collider front;
	public Collider back;

   
	if(Input.GetMouseButton(0))
         {StartCoroutine(MyMethod());}
	if(Input.GetMouseButton(1))
         {StartCoroutine(MyMethod2());}    
	}
 
 void Place2(){
	 
	 Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
             RaycastHit hitInfo;
             if(Physics.Raycast(ray, out hitInfo))
             {
			 Destroy(hitInfo.transform.parent.gameObject);}
}
 
 void Place(){Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
             RaycastHit hitInfo;
             if(Physics.Raycast(ray, out hitInfo))
             {
if (hitInfo.collider == up){
	Instantiate(cube,new Vector3(this.transform.position.x,this.transform.position.y + 1,this.transform.position.z), Quaternion.identity);}
if (hitInfo.collider == bottom){
	Instantiate(cube,new Vector3(this.transform.position.x,this.transform.position.y - 1,this.transform.position.z), Quaternion.identity);}
if (hitInfo.collider == right){
	Instantiate(cube,new Vector3(this.transform.position.x - 1,this.transform.position.y,this.transform.position.z), Quaternion.identity);}
if (hitInfo.collider == left){
	Instantiate(cube,new Vector3(this.transform.position.x + 1,this.transform.position.y,this.transform.position.z), Quaternion.identity);}
if (hitInfo.collider == front){
	Instantiate(cube,new Vector3(this.transform.position.x,this.transform.position.y,this.transform.position.z - 1), Quaternion.identity);}
if (hitInfo.collider == back){
	Instantiate(cube,new Vector3(this.transform.position.x,this.transform.position.y,this.transform.position.z + 1), Quaternion.identity);}
	
}} 

IEnumerator MyMethod(){
  yield return new WaitForSeconds(0.15F);
 Place();
 }
 
 IEnumerator MyMethod2(){
  yield return new WaitForSeconds(0.3F);
 Place2();
 }}
2

Well, you are spawning coroutines every frame. Each coroutine waits the given time, then creates / destroys the thing. They don’t wait for each other, they are not linked in any way.
How about, instead of using coroutines, you just remember when’s the last time you created / destroyed something. Then, if the mouse is held down, you check for the time, and only if the time difference is big enough, you perform the action (and also write the new time)