Aristotle thought that women were inferior to men, and cited the well-known »fact« that they have fewer teeth as evidence to support his belief. Bertrand Russell pointed out that all he had to do to check this »fact« was ask Mrs. Aristotle to open her mouth. SOEP has played the same role in research on LS that Mrs. Aristotle’s teeth should have played for Aristotle. Evidence from SOEP played a major role in overturning the previously dominant theory of LS – set-point theory – and has contributed substantially towards new lines of research directed towards explaining medium and long-term change. Our aim in this paper is to review some of the contributions that SOEP has made to research on Life Satisfaction (LS) under Gert Wagner’s leadership. We then attempt to make a further contribution by analysing SOEP data for the last 25 years (1990–2014) on the somewhat different factors which affect (1) LS change and (2) LS volatility. In doing this, we assume that the reasons why many people have fairly stable levels of LS are already well understood (Sheldon/Lucas 2014). SOEP’s contribution has primarily been to provide evidence about change. In this paper, we introduce what may be quite an important distinction between LS change and LS volatility. The point of this distinction is that many individuals whose long-term mean levels of LS show no net change nevertheless record high degrees of volatility, with periods in which their LS is well above their long-term mean, and other periods in which it is well below. There is now general agreement among LS researchers that our main current task is to develop a theory of LS which accounts for change – or, we would say, both change and volatility – as well as stability (Sheldon/Lucas, 2014). Clearly, set-point theory is purely a theory of stability and it is certainly correct to claim that there are some factors which tend to stabilise LS. But what are the variables that account for change and volatility? In seeking to explain change and volatility, we have found that conscious values/life priorities and behavioural choices play significant roles. It is likely that we have only scratched the surface in accounting for change. Future researchers will presumably find more individual choices – and perhaps public policy choices – which make a significant difference. Hedonic treadmills can then be sent to the junkyard of discarded academic metaphors