Turn (impulsive) shoppers into retaining customers. Loyalty programs that reward customers for coming back to your store can increase retention. Data suggests that 80% of shoppers are more likely to continue doing business with brands when actively participating in a loyalty program.
Often found with coffee chains where customers receive a free coffee for their x-purchase.
Be considerate. Loyalty programs won't always make sense, for example, when you're selling products with a long lifetime. If you happen to offer services (e.g. maintenance) related to that product, however, it can become a powerful driver of sales.