I feel like I comment this on every hearing impairment thread on HN, but for me invisible hearing aids are an anti feature. I prefer to wear behind the ear models as they provide a visual clue to people that I'm hearing impaired and they are more understanding about having to repeat themselves. (I started wearing them in my early 30s and I admit I was pretty self conscious about them to start with, but quickly got over it.)

Also kids notice them sometimes and are usually not shy about blurting out 'hey what's in your ears?!?' which can lead to teachable moments :)