This is another neat expression in Japanese I learned from the Japanese TV show Nihongo de Asobo:
Momo kuri san nen, kaki hachi nen
The meaning of this little phrase deals with when certain trees bear fruit. Peaches (momo) and chestnuts (kuri) bear fruit in 3 years, while permissions (kaki) bear fruit in 8 years.
While the typical Japanese person living in an urban setting wouldn’t need to know such things, it’s probably a little bit of collective wisdom that’s been passed down through the generations. Interesting stuff.