If you use a platform like Deel or Fiverr, you can set up milestones that way.

For me, I prefer to use a contract to spell out all deliverables (with dates if specified for each) AND payment plans. For example, if the client and I discuss and agree to 25% upfront, 50% at a certain point, and the rest upon completion OR maybe something like “$xxxx total to be paid in installments of $xyz on the first of the month in January, February, and March 2023.”

This way, it spells out specific deliverables and dates and the entire payment plan and totals.