Minor updates, security patches etc. via the App Store usually work just fine. Major OS updates (like going from El Capitan to Sierra) are a pain in the a. But

Minor updates, security patches etc. via the App Store usually work just fine. Major OS updates (like going from El Capitan to Sierra) are a pain in the a. But there is no guarantee for any of this, as a rule of thumb: the closer you are to "original" hardware, the less problems you will experience.