How to create automatic Estimate Reminder Email

Hello - We do a lot of Quotes/Estimates. However, we always fail to follow-up with customers on these quotes. Therefore, many times we fail to convert these quotes into orders. We want to automate the process of Quotes/Estimate Reminders.

Here is the logic we want to implement through automation:

If an Estimate is in the "sent" status for more than X days, then send an automatic Email to the Customer reminding them to look the estimate and respond.

Please help us with this simple automation.

-regards
Manpreet