It can depend upon where and how it is used. In general it is a mechanic of spelling, and if you follow the rules you should have no problem. However, some of the educational tests that we see these days make one wonder on what planet are those who set the tests. Instead of concentrating on the basics and essentials some questions appear out of context, even unrelated to the real subject.
In your case it is more important to know when to use capitals.
- For Teachers