It seems natural to talk about time in decades. We all do it. We even organize history by decades and centuries. These are convenient ways to divide up time. Decades are often used to divide up the story of an individual or a nation. But is this really accurate? Is one decade dramatically different from the one before it or after it, or do time and historical events flow along without regard to the calendar?
The "Roaring Twenties" has a colorful sound to it, but what does it really mean? Does it mean that whatever qualities that made America "roar" during the 1920s were absent before 1920 or after 1930?
To understand the 1920s one needs to think about the end of World War I in 1918 and the effect that war had on Americans who wanted to get back to leading their own lives and put the war behind them. Many of the important changes that occurred in the Twenties -- mass consumption of manufactured goods, automobiles, radio, the movie industry, the rise of suburban living -- had their origins in the previous two decades.
The stock market crash of 1929 would have lasting effects on the economy for many years beyond 1929. The effect of the automobile on America of the 1920s, profound as it was, is an ongoing saga to present times. One could easily make the case for the 1950s being the next big expansion of the use of automobiles and the decade of the superhighway.
The use of decades to describe history is a common device. But keep in mind that the story of a single person or of a whole nation does not always fit into neat ten-year segments. Sometimes it is important to stand back and take a much longer (or sometimes shorter) look to see other patterns and to find other interesting stories to tell.