Showing personalized messages according to users’ literacy level has the effect of increasing the rate of updating software. However, it has been found that habituation can occur if the users see a single type of message repeatedly. Habituation could lead to decrease the rate of updating software. Therefore, evaluating the impact of habituation on personalized messages is important but has not been previously evaluated. In addition, we considered that the timing of receiving messages might also impact the rate of updating software according to users’ literacy level. In this paper, we conducted user survey for Android smartphone users. Evaluation results show that 1) more than 77% participants did not remember the content of messages they saw more than one week before and that regularly showing personalized messages prevents habituation from occurring. 2) appropriate timing includes when the user has time and when the user is using Wi-Fi.