Well, it's looking like the receiver-in-the-canal aids are not going to work for me. The right aid has, more than once, stopped delivering sound altogether (despite filter and battery change) or gotten so staticky that it sounded like someone was frying bacon in my ear.
My theory-in-use is that the right aid is malfunctioning because my right ear canal is a tight fit. And that I sweat like a 'tit cochon in the summer here in Williamsburg, VA. I'm on my third attempt at getting a good fit for the receiver in that ear, and that's the one that I had a mastoidectomy in when I was 3. I think maybe they put the pieces back together in a way that makes it tough to cram a receiver in there.
Worth mentioning, though. As we struggled with the fit question (including whether it was indeed a fit question), I used up my state-mandated 3-month no-fault trial period. My audiologist negotiated and extra month with the manufacturer, on the basis that we had all (them included) been going back and forth so many times, when we hit the 90-day mark, I had just gotten the third set of receivers, so I still needed more "trial" period.