Unity memory management spans multiple kinds: managed memory (C#), native/unmanaged memory, and Unity native assets, with the GC not reclaiming everything and IL2CPP still using GC for managed memory.

GC, Destroy, and Dispose are not interchangeable; cleanups must align with how resources were acquired and who owns them.

Addressables require explicit lifecycle handling: releasing an acquired handle is separate from nulling the reference, ownership must be clear and releases performed as needed.

Concrete patterns show safe ownership and release: RuntimeMaterialOwner, AddressableRawImage managing textures with explicit releases on enable/disable/destroy, and proper disposing after Job completes for NativeArray.

Destroy affects GameObjects and components, but may not remove all materials/textures/assets, and destruction can be deferred until after the current Update loop.

Choose cleanup method based on how the resource was acquired and who owns it; avoid relying on nulling references as an immediate free mechanism; track ownership and ensure proper releases for assets, scenes, and native allocations.

Disposables require explicit cleanup: Dispose isn’t invoked by GC automatically; use using/try-finally patterns, and note that MonoBehaviours don’t automatically run Dispose.

Common cleanup tips include trimming List capacity when needed, Clear() does not dispose elements or destroy GameObjects, and carefully managing runtime-created materials to delete them when ownership ends.

Runtime-created assets (materials, meshes, textures) require explicit cleanup; shared assets must be managed to avoid impacting other users.

Addressables specifics: distinguish Instantiate from InstantiateAsync, keep handles until clones are destroyed to preserve lifetimes, use ReleaseInstance for manual cleanup, and recognize that scene unloading via Addressables has its own lifecycle.

Differentiate ordinary C# objects from UnityEngine.Objects: nulling helps only if there are no other references; Unity objects involve both managed and native sides with Unity-specific null semantics.

Memory hygiene overview: unloading scenes doesn’t automatically unload assets; use Resources.UnloadUnusedAssets with care since it isn’t equivalent to GC and may miss some memory categories.