Business-to-business relationships between original equipment manufacturing (OEM) suppliers and customers (brand name buyers) are an often studied issue; however, theoretical and empirical studies seldom focus solely on the suppliers' perspective. This paper examines OEM suppliers' perspectives and reports on the phenomenon of some suppliers choosing single customers while others focus on multiple customers to achieve the adaptive selling as their profit making that cause the parsimonious and complex customer strategies through the empirical studies. The study also uses mental models to analyze two specific cases of OEM suppliers within Taiwan's shoe industry in relation to what kinds of environmental changes that successful managers apply to their parsimonious and complex customer strategies. Mental models are used to map the evolution of these two OEM suppliers' customer strategies, along with their culture, competitive advantages, cooperation relationships, and environment. The study explores these five core propositions to show suppliers to employ different approach to customer strategies, and map the evolution of strategic development of Taiwan shoes companies from the 1970s through to the present day.