I think this FAQ does miss out this fact.
I had been using headphone for many years, sometime hours while working.
I started to have little of hearing loss. So becareful with your ear if you love listening.

Now I have break more often while listening to headphone and usually keep the volume moderate. And now I bought hifi so I no need to listening headphone all the time.

Listening to loud speaker is less damaging compare to headphone.
Just take good care of yourself. There is so many audiophile that need audio aid to listen.