Constant and continued upgrade of skills and qualifications is imperative in a knowledge society (Davies, 1998; David and Foray, 2003), however identifying and using effective (maximise retention/recall) and efficient (minimise time to learn) learning practices is often a challenge. Spacing Effect is a robust phenomenon that suggests that the retention/ recall of learning improves when presentations are spaced as opposed to massed (Toppino "et al.", 2002). Study-Phase-Retrieval (retrieval as a learning event), Encoding-Variability (multiple routes to retrieval) and Deficient-Processing (inadequate processing) are some of the theories proposed to explain the effect. This paper presents the observations made of a real-life adult e-Learning environment for project management (PRINCE2™) based in the UK. The interplay between Inter Session Interval, Study Duration, Frequency of Usage and its impact on Time Spent and Time to Completion are explored using the concept of Spacing Effect. The regression analysis of the key parameters showed a u-shaped relationship between spacing and total study time, largely consistent with the observations made by Verkoeijen "et al.", (2005) whilst reviewing the two-factor model of Spacing Effect proposed by Raaijmakers (2003). While the lack of data and comparable studies on the effects of Spacing Effect in adult e-Learning/management training is acknowledged, this study does provide support to the notion of general applicability of Spacing Effect (Dempster, 1987) and highlights some of the gaps that remain in our understanding of the phenomenon.