Besides the fact boredom books help boredom decrease, it also gives you memories from months ago, if you have more than one or you barely update.

I would just go back to my first, second, and third boredom books and just refresh the memories. My first boredom book was like six months ago, and just looking through the happy memories make me smile

AND ALSO SEE HOW MUCH TIME HAS GONE THROUGH

LIKE DOITSU

SIX MONTHS PASSED BY SO FAST

I WISH SUMMER LASTED LONGER

OH WHALE