Flexibility is often a keyword for people working in project-oriented organisations. It definitely influences their everyday life, since they are expected to be available and engaged anytime and anywhere and often with different types of obligations. However, there are constraints limiting people's possibilities in every specific time-space. The time-geographical perspective provides concepts for analysing constraints, by identifying: Capacity, coupling, steering or authority constraints. The aim of this paper is to discuss the time-geographical concept of constraints and analyse how they are overcame by a flexible use of time. The paper is based on two field studies. The first was conducted in twelve households and included in-depth interviews at two occasions and in between the household members wrote time-diaries during a week. The second was more extensive. Two focus groups, each with 24 persons, who all had written time-diaries, were interviewed. The conclusion of these studies is that different forms of constraints define the outcome of flexibility and that the use of time can be an expression of power.