This paper is a continuing studying about the volume of laptop spare parts, and it takes into account the users' repair intentions. We found that when a laptop is no longer working, whether it will be repaired is determined by the user's intention. The user's intention is related to the number of times that his laptop fails and to its use time, i.e., how long the laptop has been used. Therefore, this paper focuses on the volume of laptop spare parts calculation equation. First, we assume the failure process of laptop parts is a Poisson process, and the failure probability of laptop spare parts can calculate at different times. We deduce the transition probability formula of users' repair intention related to laptop use time. Finally, the equation to calculate the volume of spare parts is presented in this paper and is verified by simulation. The simulation results agree with the theoretical values. From the simulation curve, we know that the volume of spare parts will decrease sharply when the laptop use time is long. After having used a laptop for five years, a user is less likely to have a broken laptop repaired. Therefore, laptop factories could reduce the inventories of spare parts.