Coding Tips - Unity Performance

Here are some super basic tips to increase your game's performance in Unity
📌 Only run code when things change. Instead of constantly polling and checking a state inside Update, try using Events and Actions to trigger code when something changes.
📌 If polling is required, then try only running your code every N frames or after a delay. Your AI code probably does not need to fire every frame.
📌 Move code out of loops when they can be run once, before, or after.
📌 Cache references and values instead of calculating them every time. GetComponent is included.
📌 Pool objects instead of Instantiating everything. Keep GameObjects in a list and when they are no longer needed, disable them. Enable them later as needed.
📌 Never use SendMessage and Camera.main. They are slow.
📌 Do not use FindObjectOfType. Instead, serialize a reference and link it in the Editor. Alternatively, you can create a singleton and use the reference directly.
📌 Avoid Vector3.Distance and Vector2.Magnitude because they use square root calculations. When possible, use Vector3.sqrMagnitude.
📌 Manually call System.GC.Collect() during loading screens or scene transitions.
📌 If you're getting large CPU spikes from garbage collection, then try incremental garbage collection.
📌 Disable/Enable MeshRenderer's using MeshRenderers.enabled. There is overhead activating and deactivating GameObject's with SetActive.
📌 Avoid calling DestroyImmediate.
📌 Store settings inside of ScriptableObjects instead of Prefabs. This avoids redundant variables allocated for prefabs using the same settings. 

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