Don't expect to be in business long, if you do any job without a deposit! and if it is a day job, more then $300 and a new customer, I recommend you get their drivers lic, infor, and a verified credit card voucher signed, before you start the job, we still have to lock our doors in this area of the country.
For most small business, $300 is a lot of money, a thousand loss can be a train wreck, most small contractors 70% of the charges are for pay outs, money they pay others to operate the business, a $300 bill to the customer may give the contractor $90 if he is lucky, residential customers usually think in terms of their hourly rate, they usually do not understand the cost of doing business, on the other side of the issue, commercial customers that are operating a business, do understand your position.