While we know that listening to loud music can cause hearing loss, now we have a new thing to worry about when it comes to using earbuds. A study published in the Online Journal of Health and Allied Sciences has found that frequent use of earphones greatly increases the bacterial growth in the ear. If you share earbuds with a friend, say on the bus or while watching a movie on a laptop, bacteria can transfer from your friend's earbud to your ear. If that happens, it can lead to a painful ear infection. So the bottom line is to use your own earbuds, or thoroughly clean the set you're going to share.