I'm not an audiologist, but as a lifelong tinnitus sufferer and someone who was at one time responsible for buying safety equipment in a manufacturing setting, I've come across several bits of information that it sounds like some people on this thread might be interested in.

Exposure to something as loud as gunfire results in immediate and permanent hearing damage -- even just once, and whether or not you consciously heard it at the time. It may be a level of damage you don't really notice, but it will be there to add up with all the other little losses you don't notice until one day, you realize you have a problem. This is never reversible.

Temporary ringing in the ears after an exposure (gunfire, rock concert, whatever) alerts you that permanent damage of some level has been done. If you're lucky, the ringing will eventually stop; consider yourself warned and take care to avoid it happening again.

Repetitive exposure to very loud sounds that may not immediately bother you (like lawnmowers, leafblowers, etc) without hearing protection will, over time, result in noticeable hearing loss. It can take years, but it will happen.

If you have tinnitus, it is important to accept it as peacefully as you can and just get on with your life. If you allow yourself to get upset over it, this will cause central nervous system excitation that will actually make the ringing worse, creating a truly vicious cycle.

In my case, I notice that watching TV can greatly aggravate the ringing, especially certain frequencies or crowd-type noise. While my hearing is quite serviceable for day-to-day living (except when the ringing gets so loud that I actually can't hear some real-world sounds over it), I do have some difficulty with catching dialogue on TV. I found that I would turn up the volume to catch the spoken bits better, but that the louder noise level would set off much worse ringing. My solution is to watch TV with closed-captioning on most of the time, with the volume lower than normal (I turn it up for others when I am watching with company).

So, that all said, I'm in the same boat with the rest of you as far has having the bedside handgun and being faced with what to do if there's an intruder in the middle of the night. While I would love to be able to protect my ears before firing, the time taken for that would be time taken away from getting adequately prepared to deal with the worst situation in my life. If that time ever comes for me, I'll focus on getting out of the situation alive first, and deal with the hearing issues later. And there will definitely BE hearing issues, but at least I'll be there to have them.

Best luck to everyone.