Abstract People consume time and space given to them in order to participate in various activities, and the range of time and space that individuals can consume differs according to activity/travel conditions such as the working time, commuting time, the quality of transport infrastructure, etc. The accessibility toward opportunities to participate in these activities may have an impact on individual’s quality of life, and the accessibility to non-work activities has a larger impact than accessibility to mandatory activities. Therefore, the research objective of this paper was to examine how activity/travel conditions affected activity participation patterns. The mandatory activities that are not significantly affected by changes in activity/travel conditions were excluded from the research and the focus was on the changes in patterns of discretionary activities. To consider discretionary activity patterns with large day-to-day variability, multiday analysis was performed. For multiday analysis, the need-based theory suggested by prior studies was used as a theoretical background. To statistically analyze the need-based theory, a hazard-based duration model was utilized, and the general hazard-based duration model was extended to analyze the heterogeneity between latent classes. The time-use survey was conducted to collect multiday activity/travel diary data, and in order to relieve fatigue of survey respondents, the survey was simplified and conducted online. The results indicated that people's discretionary activity patterns are affected by various socio-demographic attributes, time budgets, and space budgets. In most of the activities, differences in activity patterns between the latent classes were identified. Furthermore, in this paper, the changes in activity patterns due to the opening of GTX-A (the express railway planned for the Seoul metropolitan area) were predicted using the model estimation results. Accordingly, it was found that as the GTX-A line opens and the time–space budget expands, the frequency of discretionary activities increases, i.e., induced demand occurs.