At this point I do not require deposits to begin work on standard rx7 rebuild jobs. I bill the entire balance at the end of the job. If you are asking for expensive new parts or custom services that I have to pay out of pocket for up front, then I may ask for a deposit up front.
Regarding deposits to secure an appointment in the future:
I work from home as a one man operation. Sometimes I have to run errands, parking and storage space are also very limited. For these reasons, all visits are by appointment, to let me regulate how much work comes in and when, and be sure that I have given the owner all relevant information before taking their job.
Due to fast-changing owner plans (some owners change their mind in less than a week, some do it multiple times) I do not make future appointments farther than about 48 hours ahead. This reduces the time that owners can waffle and also allows me to prioritize response to owners who are ready to move forward immediately over those who might come next week or next month.
I do not take deposits to hold spots or book future appointments. Deposits are well and fine but in order for a deposit to serve it's true purpose it has to be a non refundable deposit in the event the owner backs out leaving me without work that week, and there's no way to do an electronic funds transfer that can't be eventually reversed or charged back. Cash or USPS money order are the only truly non-reversible payment methods, and virtually no buyers can be bothered to tender deposits via those methods which makes the entire concept moot. So it's a conversation I avoid altogether; I have enough on my mind trying to run all aspects of the business already, I simply want to have the jobs show up and do them in the order they arrived, without the need for more administration or thought on my part.