1- Percentage of repeat customers is around 75% to 80%.
2- About 2% (or less) cancel appointments, but they usually reschedule do to something suddenly coming up within their schedules.
3- No cancellation policies. Things suddenly Come up in our lives that are beyond our control.
4- Living here in Florida, it's mostly the snowbirds that effect how busy things are. During the winter months I cannot keep up with the demands, I mostly focus on Restorative Detailing. During the summer months, things slow down to the point where I'm not working 24/7. I can actually take some time off in the summer.
5- The best advertisement is word of mouth, meaning that if you can rise above your local competition by wowing your customers in a way where your competition doesn't, than word will spread fairly quick. If you fall short of what your competition offers, chances are you won't be around long. Knowledge, practice (go to the junkyard and experiment) and research.
The second best way of advertising is direct mail. It can get a little pricey but by starting small, finding where the wealthier zip coded areas are and start from there. Your local USPS office is a great source.
Third, would be a website, really. This takes a little longer getting your name out there but by focusing on your immediate area you can meta-tag and key word your way on the front pages of search engines. Google maps is a biggy. Social media , not so much but by linking social media pages to your website helps grow your website.