Define what the retainer buys
A retainer may cover availability, a defined service package or a block of hours. Identify which model applies before choosing line items. Specify the month or date range in the invoice description.
Separate the included fee from extras
A monthly package of 900 and three approved extra hours at 80 should be two lines: 900 and 240. If the package already includes those hours, charging them again would duplicate the fee.
Keep unused-time rules in the agreement
Whether unused hours expire, roll over or can be refunded should not be invented when an invoice is prepared. Reference the agreement and confirm any change with the client.
Review each billing period
Duplicate last month’s invoice only as a starting point. Update the period, number, dates, extra work and any confirmed payments. This site does not schedule automatic invoices.