Amsterdam: Bicycle parking garages and lots

Bikes are the preferred (and sometimes only legally permitted) means of transportation in Amsterdam.  When I took these photos, I had no idea there were actually bike parking garages and lots in existence anywhere.  Several questions came to mind as well as I snapped away.  Do you have to arrive early to get a space?  Are the lots free or charge an hourly rate? What if it rains or snows?  How does anyone find their bike in a full lot?  Assuming you find it, how do you get it out of the mass of metal? Does anyone ever ride away only to realize that they took the wrong bike?