If you work in any branch of IT, you are going to run into licensing issues. By that, I mean every piece of software you have needs to be licensed, and Cisco is no exception.
If we look back several years, the Cisco IOS 15.0 had no licensing; it was based on an honor code. That may have worked back in the time of Camelot, but those days are gone. So, that means when you order your router or switch, you are also paying for the IOS that comes with it. But you need to choose wisely which IOS you purchase, as not all IOSes have the same features. So, you need to analyze your network requirements and choose an IOS that will meet those needs.
You might be wondering why Cisco is putting this topic into its certification. The answer is simple. A lot of people were on the honor system and, believe it or not, they did not honor it. But not only that, we have so called Cisco engineers...