Just replaced my T1 earpads with new ones. They were still in a great shape but became quite soft and squishy and I was catching myself recently on the idea that they do not sound that detailed, muffled in fact.
Wow, the soundstage grew quite noticeably and I can definitely hear more details than before.
The newer pads foam feels firm, the old is soft and easily compressed.
I have experienced similar transformation with HD650. So for you with extra mileage on your T1, consider new pads even if the old ones look fine, you'll be surprised by how much better T1 sound.
Edited by Andrew_WOT - 11/23/13 at 5:35pm