There are two good reasons not to wear headphones - awareness and hearing protection.
First, the hearing. The in-ear buds are worse than the larger headphones, and they both can be easily damage middle-ear function. This threat increases with volume and distortion, and many small devices produce plenty of both. They have very cheap amplifiers which happily distort, and the MP3 files which they play are inherently low quality. Please be kind to your ears.
Perhaps more importantly is the awareness…
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