One of the conditions JDS Uniphase mandates for its law firms are that they submit invoices every month “and should include all fees and expenses incurred through the 15th day prior to the date of the invoice.” On that schedule, a bill dated mid-month for the preceding month must cover all of that month’s time and expenses. Since I mostly consult only to law departments, I do not know whether most law firms can bill that promptly. It assumes that timekeepers put in their time fairly promptly and that the invoice generation and review process picks up its feet too.
The guidelines do not crack any disciplinary whip, unlike others I know that warn late billers that their overdue invoices may be rejected.