Yes, people take their boats to you monthly. However, people also take their boats to Best Buy. Since Best Buy gets paid (like you), does that mean they are boat experts, too?
I would like to think that I am one of the most knowledgeable shops in my area when it comes to boats (averaging 40-60 per month). I have customers that will bring their boats to me even though they drive past many Circuit City's Best Buys and even some Al&Eds, I must be doing something right. I have also been picked by some of the higher end boat manufacturers to do their high end work, again I must have done somthing right to gain their business and their trust. Lckily for you you seem to have some knowledge in the 12 volt arena. Unfortunately for most they don't have that luxury so they seek out a professional like myself. I have done numerous boats for board members and I think if I was doing something wrong we would have read about it by now. I am not claiming to be an expert I am just stating what has worked for me in the past. If I was just your average stereo guy and built subpar systems I dont think I would have the reputation that I do.