This is something that I've been thinking about lately. When your playing an adventure game, would you rather the game have, say 20 items in it, all of which are requried for completion. Or would you rather it have 50-100 items in it, of which only 20 are required and hte others are just red herrings or used to unlock extra jokes, plot bits, etc.
Also Should items be destroyable (before tehy're required) and/or destroyed in their use --- even if you use the wrong item. Or should they only dissapear after their purpose. I.e. Should it be possible to get the game into an unwinnable state?