My biggest audio-related fear is loss of hearing. I'm not deaf by any means, but I'm no longer young and I'm constantly getting older, which means that my sense of hearing is slowly deteriorating. This means that audio that sounds fine to me might sound like crap to a younger person because it is missing higher frequencies (or, worse, contains high frequency noise) that I can no longer hear.
This is actually one of my biggest fears at the moment. You must take care of your hearing as you would your heart. Having your ears checked by an otolaryngologist twice a year is absolutely non-negotiable. Also, wearing ear plugs for almost everything is essential.
If you do that, your hearing will be fine for a long time, my friend! Look at engineers like Andy Wallace or Dave Pensado. They're really legendary old wizards who would lose both legs before they'd lose their hearing.
My best wishes to you!