[dmi]

To add to this — I suffer from Ménière's disease, which manifests for me as variable hearing loss. Some days are bad, and I can hardly hear/understand speech even when someone is right in front of me and I can lip-read. Some days are good, and my hearing aids are uncomfortably loud or make things sound "weird". But most days, my hearing aids do exactly what I need them to :-)

I've had audiograms taken on moderate and bad days, and the difference in frequency response was significant (up to 30dBA difference across only the lower frequency bands).