Save your ears, you may want them later
As they note:
The maximum listening times above represent the amount of time that a typical person could listen to their MP3 player every day without greatly increasing their risk of hearing loss. It is important to note, though, that not everyone shares the same risk of hearing loss. For some people who have “tougher” ears, these recommendations are overly conservative. For other people with more “tender” ears, these recommendations do not eliminate the risk of hearing loss. Today, however, we have no way of predicting who has “tough” ears and who has “tender” ears. Hearing loss occurs slowly and is often not noticed until it is quite extensive, so early prevention is the key.