Oh no, that can't be good
I just discovered a tear in the ear pads on my Sennheiser 4.50 BTNC noise-cancelling headphones. Fair enough as I've used them for at least an hour per day on average over the last 3 years, but... I've been extremely happy with their performance so a little disappointed to have this happen.
Replacement ear pads have been ordered from Amazon to arrive in 2 week's time. Apparently originals from Sennheiser are not available in Australia. It looks like they are easy enough to pull off and hopefully easy enough to put new ones on.
I suppose I can keep using them until they fall apart completely.