I know this game is abandoned by now, but I did want to at least mention how reusable items are for the puzzles. Taking the pear as an example and going by [url="http://emshort.com/counterfeit_monkey/MonkeyPuzzles.pdf"]this[/url] guide, the pear can be used as the sole, or part of a, solution in 7 separate puzzles. Pear->ear solves both the weight puzzle and the backpacker puzzle. The guide suggests it can be used to solve the pub game, though I'm not entirely sure I understand that example. Pearl->peal solves the sound-making puzzle involving Professor Brown; Pea+Cock solves the vulgar word puzzle with Professor Waterstone, pearl->pa,pal,earl can be used in a bureau puzzle to create a distraction, and pea->pie can be used in one of the last puzzles involving opening a door in the bureau.
Not to say that there aren't one-off items, I'm sure there are, but it seems like with the openness in problem solving most of the items have multiple uses and it's something I'm very fond of.