Oh, and someone had asked about bonuses: I've worked in two offices that bonus on hearing aid sales. One of them gave $100 per hearing aid up to a certaqin number (15 I think?) after that your bonus increased to $150 per aid. That office had a lot of hearing aid patients (I usually saw one or two a day, some of the audiologists saw 3 or 4 a day). We had a quota to reach each month (mine was 20, others were supposed to reach as much as 40) and we were expected to have around an 80% closure rate meaning we sold to 80% of the people who were hearing aid candidates. The base salary wasn't great but there was a lot of opportunity to make commission.
My current position bonuses $50 per aid and there are far fewer hearing aid patients (I see one or two a week now) but the base salary is much higher and the benfits are better (so is the job security).
If you're interviewing with a place that has a bonus system, it's important to get a sense of how many hearing aid patients you'll be seeing. Also budgeting is important if a large portion of your income is based on hearing aid sales. I was in a practice in New York where summers were very busy and winters were very slow because a lot of the nearby residents went south for several months. Even the residents to stayed the winter had a lot of transportation issues and often could not make it into the office.