There are very few free/open-source operating systems that get security patches for as long as Windows does.
Major versions of OpenBSD are only supported for 5-6 years. Most Linux distributions only get 3-5 years. Red Hat promises 10 years of support, the same as Windows 7/8/10. None comes close to the 13 years that Windows XP was supported for.
So you're gonna have to update anyway, at roughly the same interval if not more often, as if you had used an enterprise edition of Windows.
