||This study explores two related concepts: (1) that brand choice is influenced by ideal brand stimulation level, and (2) that inertial and variety-seeking tendencies vary across consumers and by brands. Specifically, we develop a multinomial logit model which incorporates both inertial and variety-seeking tendencies based upon the concept of reference run-length of each brand. We define reference run-length as the previous optimal stimulation levels, which act as a reference point for the current brand-run. The findings show support for reference run-length based purchase behavior. Also, we find that renewal of brand inertia occurs when brand-run goes beyond the reference point. Implications for using reference run-length for market segmentation and competitive structure analyses are further discussed.