Decision making capabilities have outcomes of great significance for individuals and groups. Yet, decision processes and outcomes are robustly affected by a range of contextual factors, which can influence even the best decision makers. One reliable contextual factor is time. Through the lens of experimental studies and computational modelling, this presentation provides illustrative case studies of the different ways in which time impacts decision making behaviour. It will cover decision making at different scales - from individual decisions, to collective sets of decisions, through to natural variation in decisions over time. In each case, psychological theory is developed to provide a deeper explanation of the latent processes people use to make decisions, and in turn how those processes are adapted when faced with different temporal contexts and pressures.