'It's always in the last place you look,' because there is no reason to keep searching for something you already found. amirite?

Unless you find something else interesting on the way that leads you on another quest

It took me until I was about 10 to realize the logic behind that phrase.

Once I was about to go to work and needed my car keys. After looking for 10 minutes I found them and put them in my pocket. Then I got distracted and started looking for my key's again.

Nothing is fool proof to a significantly talented fool.