I have the ReSound Linx 9 hearing aids that are controlled by my iPhone. I usually don't wear them when I ride for many of the same reasons listed above, sweat, water, wind noise etc. I wore them once on a longer ride in an area where I was unfamiliar and I could listen to the turn by turn directions from my phone via bluetooth. It was a pretty handy feature but I don't think I'll wear them when I ride anymore.