You should probably check that you aren't getting an update that is failing and getting reverted which would cause it to look like it is always needing to update. How to do that... view your update history and see which update is being repeated ( if there is one ).
By default Windows will install important/critical updates without asking... you can delay those from the Update page for 7 days at a time if you wish. There are also utilities that can disable the automatic updates like WinAeroTweaker .... but then you would need to check manually or risk having a security risk left unpatched or other bug that was found out later that could affect system stability.
