It is possible to set the module to schedule email as often as you wish, from every new product added, to every 10000th product added, or anywhere in between.

If you rarely add new products, you might want emails to be scheduled on EVERY new product.
If you are a frequent flyer of new products, you might want emails to go out every 6th new product. Or every 52nd new product or every 100th - the higher the number the less frequently your outgoing email will be scheduled...

It's completely up to the end user (shopowner) to set up this number. Logic in the codebase will determine when the emails should be scheduled based on a combination of this user chosen number & the new Product ID.