Do note that you can use greater then ( >= ) in your XPaths. So you could still use a scheduled event. I would create a checkDate variable that you fill with the current date time minus 5 days. You then can retrieve all Assigneddates that are greater then that variable and process those to send out the reminder mails.
Regards,
Ronald
Usualy I first create a variable called ‘FiveDaysAgo’ like this
AddDays([%currentdate%],-5)
and second: compare the AssignedDate to $FiveDaysAgo:
$modulename/Assigneddate < $FiveDaysAgo
You could also take current date, substract the assigned date and divide the difference by 5. If you can divide by 5 and no email has been sent yet, send a mail.