Taking payment: methods, timing, what a deposit is legally, and the final-payment handoff
In one paragraph
How you take money decides how often you chase it. Card and electronic payment on the tablet at completion, deposits collected only within the cap and treated as the customer's money until the work is done, progress payments invoiced the day the milestone is real, and a final-payment handoff that trades the unconditional release for cleared funds. And no cash discount that skips the books: every dollar is income, every fixture sale is a sales tax event, and a deposit spent elsewhere is a disciplinary count.
The rule
A down payment is capped at $1,000 or 10% (B&P 7159.5(a)(3)); no other payment may exceed the value of work performed or material delivered (7159.5(a)(5)); on a service and repair contract nothing may be accepted until the work is completed (7159.10(a)(1)(D)). Money received for a specific project must be applied to it or accounted for, or the diversion is cause for discipline (B&P 7108). Fixture sales carry reportable sales tax (CDTFA) and all receipts are taxable income (IRS).
Why it matters
A contractor who collects at the kitchen table on the tablet has no receivables to chase and no 30-day gap to finance. A contractor who takes the deposit in cash, spends it on another job's payroll and gets a customer complaint has a 7108 count on the license before the panel is even installed. The mechanics of payment are compliance and cash flow in the same motion.