Hey,
90% of our clients are repaying customers, which means they usually buy the same products in various amounts, and different amounts of days, though if they won't buy it from us they will still purchase it, simply from someplace else...
We are trying to find a CRM in which we can modify a field that counts days from the previous purchases and when the number of days has passed, we'll get a notification saying it's time to make a call and offer the customer to renew his order.
Any suggestions?