Many people have mistook concentration as meditation. But we need to realize that these two are very different. Concentration is not meditation. Even I have done the same mistake until I have been cleared and start practicing. Without experiencing anything neither you or me are able to realize the truth. Experiencing is the most important thing.
When we are doing some work/activity, we keep on concentrating about what we do with the involvement of mind. But in meditation there is no involvement in the mind.
That is why it is really important to do meditation as a habit in every day of our lives. As we brush our teeth every morning , as we eat every day etc we need to practice meditation as well.
This is bit similar to knowledge vs realization. Knowledge is not realization. You can read many books as much as you like and gather knowledge and borrow the concepts from others in various methods. In this way your knowledge will be expanded but you will not realize anything. Experience is a must to realize anything.
In other words "Realization means throwing away your knowledge"