Rahul went with his father to buy hinges for the door. The shopkeeper showed two types of hinges: normal iron hinges and the galvanised hinges. The normal hinges were cheaper while the galvanised hinges were costlier. Rahul's father opted for the cheaper normal iron hinges. Rahul suggested father to buy galvanised hinges though they were costlier.
What was the rationale for Rahul to buy galvanised hinges?