As I kid summer was the best of times. The warm days seemed to last forever, as did the fun. Then school started and it was the opposite. Time seemed to tick backwards on the clock!

Now, as an adult, it seems like the clocks are accelerated. “It's almost Christmas… AGAIN!” I've found myself saying out loud. Or, “it was just New Years Day! How can it be June already!?!”

This sense that “time speeds up” as we get older is widely accepted, and looking at time passage over the past decade is especially revealing: In several studies over the last 20 years, people reported that the last 10 years of their life seemed to pass faster the older they were. 

Our retrospective sense of time hinges on memory: Periods rich in novel, significant experiences feel longer, while routine collapses duration. This principle could explain the age effect on subjective time. Childhood, adolescence, and early adulthood overflow with “firsts”—biological and psychological leaps, new skills, new places, new relationships—each adding weight to memory. As the years pass, routine gradually displaces novelty, and even changes in jobs or travel cannot recreate the intensity of early milestones. With fewer meaningful events experienced, subjective time accelerates as we grow older.

Or could it be that we just simply forget things?

Does time feel like it speeds up because we remember fewer life events? Surprisingly, the answer is no. Researchers found no link between how fast people felt the last 10 years had passed and how many autobiographical (personally significant) memories people could recall from that decade.

As we age, it seems we don’t lose richness of experience; we may even savor it more. In a way, it’s a quiet reminder to embrace the moment—carpe diem—and growing older doesn’t dull our memories; it deepens them.

So what actually makes time seem to speed up as we age? The research study points to a key factor: the gradual decline in certain cognitive abilities. Older participants—and especially those who scored lower on tasks requiring them to recall spoken words after a delay—were the ones who felt that the past decade had vanished more quickly.

Cognitive decline sets in sometime after 30 years of age, minimally, but measurable, and with a sharper decline after 50 years of age. The idea is straightforward: When fewer everyday events can be encoded in detail, the memory “density” of a decade thins out. Looking back, that sparse record makes the years feel compressed.

Researchers found that age-related cognitive decline—particularly the intake of new information—helps explain why the past decade can feel like it sped by. But that is only part of the story; other, unmeasured factors will also contribute to the link between aging and the acceleration of subjective time.

The good news comes in two parts. First, older adults actually cherish their meaningful experiences more, recalling them with greater richness.

Second, we’re not powerless: Staying physically active, socially connected, emotionally engaged, and mentally stimulated are all known to be protective factors against cognitive decline. In other words, living well with people we enjoy may help to both keep our minds sharp and our sense of time a little more spacious.