If you have more recipients in your list than your daily quota, you can tell YAMM to send automatically your message to the remaining recipients when your quota renews.
How does it work?
Every time you reach your daily quota (400 or 1,500, depending on your Google account / paid plan), and if you still have emails to be sent (there are still rows to be processed at the bottom of your spreadsheet), you will receive this notification:
This scheduling functionality offers you the possibility to let YAMM send automatically the remaining emails: If you enable this option (click on 'Yes'), YAMM will check every hour if your quota has been renewed.
When it's the case, it will continue your mail merge until it reaches the end of your spreadsheet:
Note: As notified in the warning displayed above, do not delete your draft in Gmail or your spreadsheet, otherwise YAMM will not be able to send correctly your emails.
The mention 'SCHEDULED' will appear in the 'Merge status' column to inform you that the concerned rows (3 & 4) will be automatically processed by the add-on:
Therefore, you don't need to wait 24 hours anymore (the time for your quota to be fully renewed, or more if you have a lot of recipients) to run the add-on in order to complete your mail merge, YAMM will do it for you!