This is the 10th (and so far last) part of my wishlist to audiologists and accousticians, hearing aid manufacturers, and the health care system. If you like to add something, share your experiences, or provide more information, I encourage you to submit a comment.
Most hearing aids are not waterproof. That leads to a lot of situations which are perfectly normal for hearing people but exclude hearing-impaired ones. For example: social water sports, pool parties, sauna with friends, a trip to the beach with friends, watching a movie with wet hair after you just had a shower, open air concerts in the rain, muddy festivals, listening to audiobooks or watching TV while lying the bathtub. I could go on and on. Also simply sweat is a problem for many people, especially those who perform a lot of sports.
There are a few hearing aids on the market that claim water resistance, I hope it will be standard and affordable soon.
See also the previous point on my wishlist: Legal certainty for situation related to broken hearing aids.