InvoicePlane currently supports recurring invoices, but in practice many businesses need to bill for both once-off items and recurring items in a single invoice.
So the feature request is:
Allow recurring invoices to be edited (not the original invoice, just the next recurring one that is due to go out) so that items can be added that will only appear on the next invoice (and not recur).
Take the example of a client who has several hosting packages. These are recurring items that need to be billed for every month, ongoing. They would be put into a recurring invoice.
But if I do work for that client during the month, and charge by the hour, this is not a recurring item - these items are only billed once-off.
It would be great if these items could be added manually (during the course of the month) to the next recurring invoice. Then at the end of the month, the recurring invoice goes out. It contains the usual recurring items but it also contains the manually-added items. And since those items are not in the original invoice, they do not recur after that invoice.
This would be a great feature, and would probably spur adoption of InvoicePlane among IT service companies and other businesses in the service industry. Although I realise it is a big job - perhaps there is another way to achieve the same result?