Cap,
  Do you have a shop camera? If not it would be a cheap and wise investment.  Nothing beats a he said,she said like a picture.
    If I was still in business I'd be using it on every job!
    
 i've got security cameras now. 2 in the office, and 1 in the shop. i'm upgrading soon to 2 in the bays, 4 outside, and keeping 2 in the office. in addition, i keep a digital voice recorder in the office. i record nearly everything audio in the office. 
 also, i have a digital camera and a digital camcorder. i use those to help educate my customers. if they're not here when i find a problem, i'll video or photo it in order to show the customer why i sold them what i sold them. i figure someone that knows exactly why i'm charging what i am, is a customer that'll come back over and over. 
 i was just looking at a contour hd camera, which is pretty small, and great quality videos.....those can be headstrap mounted, which would be good for recording the entire job.