Mother Memory

When Benjamin wanted his blue caboose, I remembered that it was upstairs, in the corner, under a pile of little people toys.
When Benjamin wanted his Timberland sandals, I remembered that he had taken them off and left them in the car two weeks ago.
So why can't I remember where I put either of the two hammers?

And why might I need one or two hammers?
Maybe it's good I can't remember where the hammers are...