Out of the phones I have used recently:
Plantronics for my PC - 12-14 hours at a time if playing a game. I rarely do this anymoore, but they are not fatiguing.
Sony EX71 - 2 hours max if the volume is low. If I turn them up enough to hear the mids clearly, I can only listen to them for about 45 minutes before having pain in my ears.
PX100s - at night with low volume, 3 - 4 hours before I drift off to sleep. If I am out walking and they are turned up, I can listen for about 2 hours before I want to take them off. There is no real pain, just a mild discomfort that is difficult to describe.
Westone UM-2 - I've never worn them for more than 4 hours. This isn't due to fatigue or discomfort, but that I don't have the opportunity to wear them longer than that. I listen comfortably at very low volumes with them. Using my mini, at night I listen at the first notch on the bar, and outside I listen at about 1/8 - 1/6th. If I turn it up louder than that, I can no longer hear traffic around me and that makes me nervous.
I have minor tinnitus. It might be more related to muscular or vascular problems than hearing damage. I know I have suffered some damage, but my tinnitus is aggravated / louder when I turn my head, or am laying down. If I am walking around or standing in a quiet room, my ears ring but it is barely noticable. If I am laying down, it is loud enough to keep me from sleeping if I am already having trouble getting to sleep.
