To avoid gaps in active invoice #, we should only associate an invoice # when the draft is sent or mark as sent.

Some of our invoices are created as drafts to keep track of our different incoming invoices for the same project. We send them at different milestones of the project. So, during the time that we work on a project, and it can take months, we can send many other invoices. This is where the gaps between invoice numbers is created.

So, drafts should have their own numbering (i.e : DRAFT-01) and get their invoice number when sent.

We can't use "Quotes" because theses invoices are already accepted, it's just that the project isn't finished yet.

We can't use "Recurring invoices" because these are not recurring invoices, we can't know for sure when the next invoice will be sent.

Thanks