Customer loyalty according to Sindel (2000: 20) "The state of mind or an attitude in which the customer has a desire to purchase a product or service offer in preference to a competitor's alternative" or "loyalty is having or showing continued alleviation; tangful to one's country, government, brand, etc. "Meanwhile according to Kotler (2003: 294) loyalty is" Adeeply held commitment to re-buy or re-patronize a preferred product or service in the future despite situational influences and marketing efforts having the potential to cause switching behavior ".
From the above opinion it can be concluded that customer loyalty is an emotional feeling that occurs between the customer and the company that makes the customer willing to make a relationship with the company, in the form of product purchases over a long period of time.
In addition to the subscription period and continuity, an important aspect that should not be forgotten if we discuss customer loyalty is the emotional connection between the customer and the company. With the feeling of closeness and comfort, satisfaction, trust, and a feeling of belonging to the company created in a relationship with the company is an indication that there has been an emotional connection between the customer and the company. And it is this emotional connection that keeps customers loyal and encourages them to continue subscribing with the company and is willing to recommend products from the company to others, friends and family (Barnes, 2001: 30-31).
The basis of loyalty is the effort to maintain and increase customer satisfaction. For this the company needs to add value to the products the company offers to customers. What is meant by value here is what customers get from what they give when interacting with the company (Barnes, 2001: 33-87).
Customer loyalty according to Sindell (2000: 21-23) can be categorized into seven types of loyalty, namely:
a. Monopoly loyalty, is loyalty that occurs because customers have no other choice. In this type of customer has a low level of love and a high level of repurchase.
b. Inertia loyalty, in this type, customers do not want to look for alternative companies, customers in this type have a low level of love, a high repurchase rate, and have a low level of satisfaction with the company. Customers like this are easy to be taken by competitors who can show the benefits of moving to another company.
c. Latent loyalty, the customer actually wants to buy a product from a company, but internal purchasing policies or environmental factors make it difficult for customers to make repeat purchases.
d. Convenience loyalty, is loyalty caused by the customer feeling comfortable interacting with a company.
e. Price loyalty, is a type of customer loyalty, where customers are only loyal to a company because the company offers lower prices than other companies.
f. Incentive loyalty, is a type of loyalty where, customers are only loyal to a company only because the company provides rewards to customers who are consistent in making purchases of the company's products.
g. Premium loyalty, is a type of loyalty, where customers have a high level of love and repurchase of products or services from a company other than that in this type of customers emotionally really feel the benefits of a product