The brand accessory market has become increasingly important. Some recent examples include screen protectors, case covers, and home button stickers for iPhone in Korea. Providing brand accessories is one strategy for maintaining desired level of stimulation while controlling sensory satiation. An important determinant of the success of brand accessories is its complementarity to the base product. Complementarity has been conceptualized as the relationship between the base product and the accessory. This research investigates the role of two factors - (1) the benefit congruence between the brand concept of base product and brand accessory and (2) the moderating role of consumer's brand schematicity - on the incremental value of base product with an accessory. The author proposes that the evaluation of base product (aesthetic brand versus functional brand) with an accessory (aesthetic brand versus functional brand) is subject to an asymmetric additivity effect. This asymmetry is because aesthetic additions enhance the sensory pleasure of using a functional brand, whereas functional benefit additions may dilute the existing sensory experience of an aesthetic brand. This study empirically tests the relationships between the brand concept of base product and brand accessory while exploring the moderating role of consumer's brand schematicity. The findings of this research suggest the importance of a brand strategy. Finally, practical implications for further research are suggested.