Customer
In sales, commerce and economics, a customer (sometimes known as a client, buyer, or purchaser) is the recipient of a good, service, product or an idea - obtained from a seller, vendor, or supplier via a financial transaction or exchange for money or some other valuable consideration.
Experience
Experience is the knowledge or mastery of an event or subject gained through involvement in or exposure to it. Terms in philosophy such as "empirical knowledge" or "a posteriori knowledge" are used to refer to knowledge based on experience. A person with considerable experience in a specific field can gain a reputation as an expert. The concept of experience generally refers to know-how or procedural knowledge, rather than propositional knowledge: on-the-job training rather than book-learning.
Experience
Learn the lesson of your own pain—learn to seek God, not in any single event of past history, but in your own soul—in the constant verifications of experience, in the life of Christian love.
Mrs. Humphry Ward, Robert Elsmere, Chapter XXVII.