I have a list to track few tasks assigned to a group. I have multiple columns and relevant to this issue is open date, closed date columns. Need your expert assistance to send reminder emails to the group if the task is older than 3 days.
Make a 2010 workflow that sends out an email. (Due to SP2013 it has to be a 2010 workflow, 2013 workflows are not allowed for various reasons)
Under List Settings - > Information management policy settings -> Retention Settings -> Choose a content type (Item?). Click enable retention -> Add a stage.
Using a date column (Open date or created/other date field depending on what columns you have) + 3 days.
Under actions choose workflow and select the 2010 workflow you made.
In this case you could create a workflow from the SharePoint Designer 2013. How to do this you can read in this post: Send e-mail in a workflow
But there are some limitation: you can't specify custom
Bcc: addresses, include images, custom css to modify email template, and so on.
So if you are not willing to use complex SharePoint Workflows, the possibilities are quite limited. In this case it is an option to use a 3rd party tool, to extend the SharePoint alert feature. You can find some options in the market, but I would recomend you the JungeBell alert and reminder tool.