THE TIMING OF UPGRADES*

By using a durable‐goods monopolist model, this paper investigates the timing of upgrades. I consider a three‐period model where the monopolist can upgrade the product in the second and third periods by investing in R&D. I analyse the non‐commitment and commitment cases. In the latter case, the decision on the timing of upgrades is made in the first period in advance. It is shown that the time‐inconsistency problem causes the monopolist in the non‐commitment case to release a new version more rapidly than in the commitment case. Moreover, even in the non‐commitment case, the release of a new version can still be later than the optimum from the social viewpoint.