Reminder ads are a popular strategy that retail companies use to jog the customer’s memory and promote customer activities. Companies normally send these ads, usually through email, text or app channels, within 30 minutes to one hour of a customer leaving the company’s website or abandoning their cart. But is that the most effective time?

According to new research from Xueming Luo, sending reminder ads too soon can trigger feelings of annoyance and thus lead consumers to purchase less. Luo says the best timing for these reminder ads is between one to three days. This range, he argues, gives customers enough time to want their memories to be rekindled, but it is also not long enough for them to completely forget about the products.