The more you rely on antibiotics, the less opportunity your immune system has to develop itself.
Your body has natural bacteria living throughout that are required for survival. Antibiotics cannot target one single strain of bacteria. Rather they are fairly indiscriminate about what they kill, so that every time you use antibiotics your body is being depleted of the normal regulating bacteria.
Over the years many types of antibiotics have become impotent as the bacteria mutate to form different strains, so stronger, more advanced antibiotics are required to do the same job.
Now researchers are recommending that antibiotics are not used as first option for conditions such as otitis media (middle ear infection). This is due to the fact that most middle ear infections are viral (around 80%) in which case antibiotics will have no positive impact, and a wait-and-see approach is now commonly recommended.