How long do messages stay in outbox

I am using eM Client + GSuite

When I turn off the setting to send mail immediately,  how long will emails stay in outbox before they are sent?

I remember in Outlook there was a Send & Receive schedule you could define. 


If you have used delayed send, then the message will upload at that specified time, otherwise they will remain in the Outbox until the sync schedule that you have defined in Menu > Tools > Settings > General > Synchronization.

This setting also affects contacts and calendars. The Inbox will always be synced in real-time when using IMAP regardless of what you set here.

Thanks Gary. I can’t believe I missed that! 

Really appreciate the help!