Omitting the word ummm...

Business communications class gives valuable information to those hoping to enter the business world. Currently we are learning about the different types of interviews and how to prepare. Also apart of the class is making presentations. One thing that the teacher has stressed is not using the word ummm... In talking with the teacher one day after class, she told me personally that I need to break this habit for my own good. I did not realize how much I used it when I was trying to think of something to reply to a question, especially in that conversation. She told me that you will sound more confident by not using um as a filler word for silence. Another thing she said was that it takes 21 days to break a habit. So far it has been 5 days and I still catch myself saying um. So I still have 16 days left to ummm...break the habit.