A payment tied to completing a defined project stage rather than a calendar date, releasing money as agreed deliverables are finished and approved.
A milestone payment ties money to progress instead of the calendar. On a $9,000 project you might split it into thirds: a third to start, a third when the design is approved, a third on launch. Each release is earned by finishing a defined chunk of work.
For sellers, milestones keep you from carrying weeks of unpaid work — you’re paid as you go, and a client who stops paying can’t string you along indefinitely. For buyers, milestones tie your money to results you can actually see, not just elapsed time.
The trick is defining each milestone around a clear deliverable, not a fuzzy stage. “50% when the homepage is approved” beats “50% halfway through” — the first has an obvious trigger, the second invites arguments. Anchor milestones to your statement of work so both sides always know what triggers the next payment.