I've been hard of hearing since I was born, and wear hearing aids on both ears (the behind the ear kind, that is). Because I've flown quite often, I don't ask for clarification when it comes to those safety announcements the FAs usually make - I pretty well know the procedures anyways. But there's one thing I don't like to miss - and that's the boarding announcement at the gate. I have to ask the gate agent to simply let me know when my flight is boarding. This means I preboard the plane along with the seniors and mothers with small children. I don't have any problem with that at all. In fact, it's more of an advantage over regular boarding.
An interesting thing about inflight announcements is that if your hearing aids have telecoil capability, you can switch to telecoil (also referred to as the telephone switch) and listen to the IFE on your headphones and cut out the background noise at the same time. Not to mention that if the captain's announcement on the PA will also override whatever you're listening to on the IFE headphone. This means that you can make out what the captains just said without worrying about the background noise of the aircraft in flight. Of course, not all planes have IFE, especially turboprops and probably RJs too. In that case, you might have to ask the FA
or another passenger if you want to know what the captain just said.
Speaking of emergency exit rows, unfortunately I have been told that disabled persons are prohibited from sitting there for very valid safety reasons. I know such rules are indeed set up by Tranport Canada and while I haven't flown any US airlines for a very long time, I believe the FAA and the DOT have similar rules too.
Interestingly, the next flight that I have booked so far is to Winnipeg for a conference set up by the Canadian Hard of Hearing Association near the end of May, although I might also end up flying to Vancouver before that conference.