https://www.huffingtonpost.co.uk/entry/time-perception-aging_l_63973dc2e4b0169d76d92560
When you’re looking back, the less rich your representation is, the more it’s going to seem like the time went by quickly.”
In other words, our brains lump time together when the days or weeks are similar. So for an 80-year-old who largely does the same thing every day, the year is going to blend together in their mind and feel like it went by quickly.
The new and exciting things in a day are what make the days and months feel different, and thus set them apart in our minds.
How my heart sings 