I also bought one of those that hangs behind my ears, because the doc told me those in-the-ear aids have a tendency to hear one's own voice when talking. My insurance benefit allowed for a budget a $3,500 per ear, but I purchased the pair that cost $3,000 total.
I had to return several times to have it "adjusted." I use it occasionally when I think there will be soft-talkers or too much background noise. It eats batteries like candy. I could use it for a few hours or a for up to four hours, but the battery is dead by the time I use it again - even when I remove the battery from the hearing aid.
I'll be taking mine to Chicago.