I'm not sure where you read that from -- Preview updates are proposed updates that would be released in the next update --- it doesn't matter what level of user you are. Whether you are an 'average Joe' to an IT Professional (in my case).
Unless there are specific reasons why you are not installing a preview patch (such as application incompatibility with other enterprise applications) there is really no reason whatsoever not to install those previews as the security holes will get patched the following month. You are simply leaving yourself exposed to whatever vulnerablities that are out there -- same goes with many 'optional' ones too...
Aside from Silverlight and Windows Live Components (but that was later retired) -- I would strongly recommend the optionals too -- I know that a lot of the paranoia about windows updates came back from the mid 2000s where yes, patching was a nightmare and it has wreaked havoc in the past...
But MS has been doing a pretty darn good job of QAing releases now days and really for the average user, there shouldn't be anything hidden aside from language packs.
Finally, recovery options and uninstalling updates from Win7 on up has been a breeze now, so if you are part of the less than .0000001% in the world that has problems, System Restore or simply uninstalling it from the control panel is easy.
I hit pretty hard on the Win Updates as I used to work in the InfoSec side before going to infrastructure, and a good portion of malware nowdays simply falls into two main categories for living -- one is the social engineering (fake websites, tricking a user to provide PII, etc) or exposed and vulnerable computers...the second part is easy to fix...patch your machines...the first, takes a little more work...
But in any event, I would be happy to answer any other questions -- that being said, if you still need help, let me know
