ComponentCache.cs

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

//Create and call getcomponent through it instead.
public class ComponentCache
{
    private GameObject owner;
    private Dictionary<Type, Component> cache = new Dictionary<Type, Component>();

    public ComponentCache(GameObject go)
    {
        owner = go;
    }

    public T GetComponent<T>() where T : Component
    {
        Component val;
        if (cache.TryGetValue(typeof(T), out val))
        {
            if (val != null)
            {
                return val as T;
            }
            else
            {
                var comp = owner.GetComponent<T>();
                if (comp != null)
                {
                    cache[typeof(T)] = comp;
                    return comp;
                }
                else
                {
                    return null;
                }
            }
        }
        else
        {
            var comp = owner.GetComponent<T>();
            if (comp != null)
            {
                cache.Add(typeof(T), comp);
                return comp;
            }
            else
            {
                return null;
            }
        }
    }
}