Eli5: Why, if at all, does it seem like the years go quicker as you get older?

Question

I hear a lot of people making that remark, that the years go by quicker as you get older.
For me, at least, it seems like that’s only the case if nothing much changes in my life in that year.
To me, years seem to feel like they go slower if there’s lots of new/different things happening.

In: 348

Answer 1

When you are a kid, say 10 years old, the totality that you have experienced are those 10 years. Every year you have lived was 10% of your total life span.

When you are 40, every year you spend is now 2.5% of your total life span so it seems like every year goes by quicker because each year is a smaller percentage of your life