Time is an essential element of daily existence that each person encounters in all facets of their lives. Age-related differences in how time is processed do not contradict the theory that the neural clock system is capable of functioning from a young age. The current study investigated how the variation in longer and shorter duration for onboarding processes affect the experiences and the age-related changes in perception of time duration from 0.2 s–3 s. Participants encompassed both children and adults who engaged with user interface (UI) set featuring distinct time durations and interfaces. To summarize, the longer intervals are associated with heightened cognitive demands on users, suggesting that as time durations extend, the cognitive resources required for precise temporal estimation concurrently increase. This insight holds practical implications for user interface design, emphasizing the imperative to adopt user-friendly and cognitively efficient strategies when designing interface elements and interactions linked to protracted temporal intervals.