Loudness

• A common concern about earphones is that, due to being directly inside a person's ear, they're capable of causing serious hearing damage if they're consistently played at a loud volume. This is partly due to the inefficiency of earphones in blocking out background noise, which traditional headphones are often better at (due to having extra cushioning and covering the entire ear). This causes the user to turn the volume up when using earphones in order to compensate.
  
  

Eardrum Pain

• It's possible to experience pain when using earphones, due to their positioning within the eardrum. Although some models will be more comfortable than others, users should take care not to push their earphones too far inside their ears. This problem can be made worse if the user has any pre-existing ear pain, or is prone to dry or sensitive skin.
  
  

Sound Quality

• Although the sound quality of earphones will vary depending on the model, a common criticism is that they're less able to replicate low bass sounds than a pair of traditional headphones. To resolve this, some users may opt to increase the bass frequency in their music, which can normally be done by adjusting their music player's EQ settings.
  
  

Hygiene

• Sharing earphones can be considered unhygienic. This is due to the potential for earphones to collect a user's earwax, thus making them undesirable for other people to use. The collection of earwax could also affect the sound quality of earphones, so it's important to regularly clean your ears if you intend to frequently use earphones.