4000 hours of Garrett engines droning away is whats done for mine. Not that 15 years working with grinders etc in oil yards etc did me much good before that.
Although the seat change did mean that instead of having one !!!!e ear the other one is now also !!!!e. Although I am told I have good hearing for a TP driver. The 737 boys tend to have bad hearing as well especially if they go onto speaker in the cruise or have one muff off.
They honestly arn't that fussy with the hearing, I presume it was so all the RAF mates could get a civi medical. Some of the ex rotary boys blow your head off if you don't sort the station box out before you plug in.