In this dissertation I focus on two considerations that influence the product strategy of a firm. The first is consumers’ choice and its influence on a firm’s product offering, and the second is the interaction between durable products and their contingent consumables. First, I study the assortment planning problem for a firm; I illustrate the complexity of solving this product selection problem, present simple solutions for some commonly used choice models, and develop heuristics for other practically motivated models. Second, I study the incentives of a durable goods monopolist when she can lock-in consumers through a contingent consumable. Adopting a lock-in strategy has two interesting effects on the incentives of a durable goods manufacturer. On one hand, by locking-in consumers to its consumable, a durable goods monopolist can curb its temptation to reduce durable prices over time, thereby mitigating the classic time inconsistency problem. On the other hand, lock-in will create a hold-up issue and adversely affect consumers’ expectations of future prices for the consumable. My research demonstrates the trade-off between time inconsistency and hold-up, and derives insights about the conditions under which a lock-in strategy can be effective. I further analyze the trade-off between time inconsistency and hold-up associated with lock-in in the presence of consumable stock-piling. My findings indicate in the presence of consumer stock-piling, lock-in has an effect similar to that of competition in the consumables market: they help to dampen the hold-up problem that arises from lock-in and at the same time increase the manufacturer’s incentive to reduce durable prices over time. / text