Yesterday, Mike went to the dentist for his six-month check-up. Two weeks before he went to the dentist, he called the office to make an appointment. The day before his check-up, the office's receptionist called him to confirm his appointment. When Mike arrived at the office, he checked in with the receptionist and then waited in the waiting room for 15 minutes, reading a magazine, before being greeted by the dental hygienist, who escorted him to an examination room. The dentist entered the room, greeted Mike, examined Mike's teeth, took a set of x-rays and asked the dental hygienist to clean Mike's teeth. When his teeth were cleaned, the hygienist told Mike he should return in six months for another check-up. Mike experienced the _____ element of the dental office's services marketing mix.