"I don't believe it: another year has flown by-it seems that time is going by at an ever-faster rate." This often-expressed perception of time, actually the speed of time, is both qualitatively and quantitatively explored herein. While the speed of time is clearly invariant (at least on earth and at speeds that are orders of magnitude below the speed of light), there is ample and plausible evidence that serves to contribute to our perception of a faster moving time. More specifically, it seems that both nature and nurture impact or influence our perception of time, in particular, the speed of time. In this paper, we briefly review the cognitive and related literature to understand why the older we get, the more we perceive the speed of time to increase-there is a clinical reason for this nature-related aging phenomenon. We then show that nurture-related or experiential factors can also affect our perceived speed of time. More specifically, time series data that concern factors which impact our daily lives can be used to model or correlate with our perception of time. It is suggested that nurture reinforces and about doubles nature's impact; that is, the older we get, the more we perceive time to be speeding up. Interestingly, when age is controlled, the experiential data suggests, for example, that a 62-year-old in 1997 perceived time to be about 7.69 times as fast as that perceived by a 62-year-old in 1897; this phenomenon is less extreme for younger aged persons. Finally, it should be noted that understanding the way we perceive the speed of time over time is not only an important endeavor in its own right, but it also has a potentially significant impact on our ability to cope, on our work productivity, on our lifestyle, indeed on all aspects of our life.