Under different modes of competitive pricing behavior, profit-maximizing price trajectories are derived for durable products in a dynamic duopoly. Open-loop co-operative and non-cooperative pricing behavior is analyzed within a comprehensive model where sales of differentiated products are described by interlocked diffusion processes with realistic demand characteristics. Because of analytic complexity, the optimal trajectories implied by the control and differential-game problems are derived numerically across an extensive set of plausible market scenarios. Manipulation of initial market conditions enables derivation of optimal competitive pricing as a function of timing of entry.