Prevent Contacts receiving emails twice

When creating a product workflow how do I prevent clients with multiple products from receiving duplicate emails?

I’ve tried creating it as a contact workflow but this doesn’t give me the field options I need for the products.
But some clients have 15 or 20 products and last time they received multiple emails (angry clients!)

Hi @ECross8,

Could you specify what you mean with a product workflow? HubSpot has contact-based, company-based, deal-based, ticket-based, quote-based, conversation-based and feedback submission-based workflows – I’m not aware of product-based workflows. Is this a custom object you created in your portal?

Can you share a screenshot of your workflow?

Best regards

Yes, it is a custom object (sorry, I’m still learning!).
Is that why certain options are only available within this object and not others?
I just want the clients who have products that meet certain criteria not to receive the email more than once - any idea how I might filter it?