Did the unused assets affect the final game built?!

Hi,
When u finish ur game, Deleting the usless and unuseds prefabs objects Materials … etc , will make the game better ?
Or no need because unity3d reconize the usless things ?!

Only the assets that are referenced in scenes built into the runtime are included in the runtime build. In addition, everything in the Resources folder is included because all of those items can be referenced at runtime.