It’s worth knowing that there are many good reasons when monitoring recorded sound (either on headphones or on monitors) to listen at a quite moderate level indeed.

If you don’t have a sound level meter, from experience a good rule of thumb would be that if you were a producer sat in front of a recording console with an engineer; you should be able to talk quite freely with them back and forth without needing to raise your voice at all, whilst the music is playing back.

70, 75, 80, 85 decibels at very most is widely considered to be best practice depending on the working regulations and recommendations in different parts of the world. They do vary and have changed over time getting lower. Its also worth realising that a given sound level measurement that works wonderfully in a sizable control room at a professional recording studio, may make a whole different impression on one’s mesmerized ears and brain, in the far more restricted confines of a much smaller room.

Hearing a loud peak of sound is not what damages the delicate hairs within your ears. What causes damage is the average level of sound (contrary as that might seem to common sense) over many, many hours of listening. That is the main stimulus the ear responds to. Therefore, it is the length of time, the number of hours of average exposure, that you should be most mindful of, control and limit, not simply the level alone.