Eye see

Elder Son is ready to leave for school.

Me:  Do you have your glasses?
He:   No.  Could you go get them?

I run to his room to fetch them and notice an eyeglass case on his bedside table.  So, I grab both.

Me:  Do you need this eyeglass case?
He:  No, I've got a case in my backpack.
Me:  You have two cases?
He:  The one I take to school is my good one.  (He gestures at my hand.) That one is my...
Me:  Your "just in" case?
He:  Yeah.