Since 27 January 2016, Microsoft recommends that Cumulative Updates be installed with the same confidence as Service Packs, and installed as they become available.
The official announcement was posted on 24 March 2016 (their emphasis):
As of January CU releases, these caution messages have been updated, we now recommend ongoing, proactive installation of CUs as they become available. You should plan to install a CU with the same level of confidence you plan to install SPs (Service Packs) as they are released.
[Note: This guidance is also posted in the latest Cumulative Updates themselves, if you need additional proof to show your boss.]
This is new guidance and shows more rapid and proactive support for SQL Server from Microsoft.
With that in mind, I would strongly recommend that you make sure your production instances of SQL Server are up to date by installing the latest Service Pack and Cumulative Update for your instance.
If you would like to know what version you’re currently running, issue the command SELECT @@VERSION against your instance.
For example, my latest instance on a virtual machine I use is 12.00.4436.
Using the version matrix on the Microsoft SQL Server Version List, I know that this instance is running SQL Server 2014 Service Pack 1, with Cumulative Update 4.
It also shows that there is a newer Cumulative Update (CU 5) available, which will bring my instance up to the very latest version (as of this writing).
Brent Ozar Unlimited has a simpler site, SQL Server Updates, if all you want is the very latest Service Pack or Cumulative Update for supported versions of SQL Server.
If you have any comments about Cumulative Updates, Service Packs, or your favourite kind of chocolate, feel free to reach out to me on Twitter at @bornsql .