Cumulative updates, service packs and hotfixes should be an important part of any on-premises SharePoint Admin’s life. They not only fix up a lot of bugs in the product but also contain important security fixes!
So the advice is to apply service packs when they arrive, well I suggest waiting it out a few weeks and look up the known issues before you apply it in your PROD environment. You should always apply any updates to a non-production environment first with similar content and code to simulate the same process in PROD.
While Cumulative Updates are to be applied specifically when you have an issue fixed by it, I recommend you keep a close eye on the security fixes that come with Cumulative Updates and then decide accordingly.
Again, don’t rush to apply a Cumulative Update just for the sake of it. Many Cumulative Updates have had serious issues in the past and there’s no easy rollback!
So how do you keep up with whats the latest Cumulative updates, Service packs and hotfixes for SharePoint & SQL?
No need to google any more if you bookmark these “Update Centers” from Microsoft. They provide an easy way to look at whats the current version of Service Pack and Cumulative Update and hotfixes for SharePoint, SQL and related products.
Update center for Office, Office servers, and related products
This includes SharePoint Server, Office Web Apps and Project Server
(This Update Center has an RSS Feed too, so you can subscribe to it).
Update Center for Microsoft SQL Server
Updates for App Fabric 1.1
There is no “Update Center for AppFabric”. I recommend a search in the Microsoft Support site for “Cumulative Update Microsoft AppFabric 1.1”