Under the customer view screen, you can see under invoices -> 'Status' ; a icon notification when an invoice is 'Email Sent'.

It would be great if we can get a similar icon for Estimates sent as well! If you go inside an estimate view, of course you can scroll down... but why not just mirror how the Invoice section does it.

Quickly verifying if estimates have been sent / submitted I believe is just as important as the quick-view under Invoices.

Thanks