Reminder email for outstanding invoice?

I send a reminder two working days next to the due date. That way, I can be sure that the money is not still on its way, but that the transfer is taking a while.

I don't know if there is actually legislation regarding how many reminders you can send and when you can send them. I would think not, but there may be legislation regarding what you can charge as additional costs.

I always follow the same schedule for myself: first reminder two working days next to the due date. If no payment is received within five working days, I call the customer.

But to each their own, I suppose ;)

I'd like to pick up on this, because what do you do if the customer actually has to pay x% extra for being late? Do you create a new invoice here? What if this is then paid late again?

No, no new invoice, but good question. My accountant used to do this via my bank accounts. If a customer ended up paying 103 euros (let's say) and they had to pay 100 euros (so 3 euros extra for late payment), my accountant would book 3 euros as extra turnover, which is not subject to vAT (an exception, I think).

You can probably do this via the reports -> start income statement. There you can manually enter something for small corrections (or effectively to transfer your previous accounts). But it's also possible for a small correction, for example, that extra bit that the customer paid. That should be correct.