Sending invoices to customers. Clicking the Email Invoice button, will use 1 unit of your quota. Recurring invoice schedules, such as auto generated monthly invoices, consume 1 unit per invoice generated.
Sending a copy to yourself does not consume additional quota.
Do automatic payment reminders to customers count?
Automatic reminder emails to clients, such as payment due and overdue reminders do not affect your email quota.
What about product notifications sent to me?
Any emails sent to you from your OSO Books toolkit, do not affect your email quota. For example, low stock notifications, or notices regarding recurring invoice scheduling.