Taking classes outside of your major is an important step if you are undecided about your major or if you are not entirely sure about the one you did choose. One extra class a semester will not hurt you and if you can schedule it in, it's a great use of time. The simple fact is that many students going to school do not know what they want to major in. After two or three semesters of taking classes, they decide to change their major and are left with nothing to show for the previous classes they took.
Most majors require very different courses and changing your major will delay your graduation date significantly. Going into college, it would be ideal to know what major you want to go with and follow through with it for four years and graduate (even though the stats show that this is a rare occurrence). Taking a variety of classes to complement your core classes will give you a bit of leeway in case you do want to change majors. It would still be like starting all over, but those 12 to 15 credits you accumulated will skim one whole semester of work.
If you decide to take this advice, try taking some classes that apply to your second or third major selection. If possible, find some classes that would fulfill the requirements for multiple majors you are interested in. You also do not have to choose the hardest possible classes for your major; after all, you might not need them in the future. Take some easy classes and make sure you enjoy the subject and have a legitimate interest in it. Who knows, maybe taking some of these classes will open your eyes to new possibilities and new career tracks that you enjoy more than your current path. On the other hand, maybe you will take these classes and absolutely hate the subject that you thought you would enjoy. Either way, these extra classes are a real eye opener and often help students choose a major for good or even have it develop into a minor degree.
Another great reason to take these extra classes is for the possibilities that they offer. If you find that you enjoy your extra classes, use them towards a minor to further enhance your degree weight or simply take them as extra knowledge that you might find useful later on in life. You never know when things come up and these classes will be practical for you.
Taking classes outside your major can also open you up to new ideas and opportunities. The main benefit here is the new professors you will have access to that are normally not available to those in your chosen major. New teachings, ideas and opinions from other professors provide a new perspective on learning the material rather than the standard teachings of the close-knit professors in your major.
Whatever way you decide to pursue the extra classes, one thing is for sure, you will find them very useful and they will help you solidify your intended major or help you pick a new one as quick as possible. One way or another, you cannot loose with this strategy.
The most important step you could take is going to your academic advisor and exploring your options. They will be happy to point you in the right direction and will help you make a more informed decision.