Flexible Date on Invoices?

Can you use a recurring invoice for this?

Don’t think so? I don’t know if recurring invoices are connected to payment. Would they send a new one each month even if not paid online? 

But you would mark it as paid every time you get a check right?

You could set up a recurring monthly invoice and then just mark it as paid once you receive the check.

Yes! Recurring invoices work for this. I have a client on retainer who pays me by check. When they pay, I mark it as paid manually. It will send the invoice regardless of whether they pay or dont (even though they've never missed a payment)..