How long can hard cheeses last in a refrigerator? I had chunks of various hard cheeses, mostly parmesan, in my refrigerator for varying lengths of time.  Some as long as 3+ months.

I've never seen any obvious signs of spoilage and have never been struck down by food poisoning after using said cheese.  But my wife is very suspicious when using any food that has been in the fridge for longer than a week.  

Is there a generally accepted length of time to keep these types of hard cheese?
Hard cheeses (e.g. parmesan) will typically last several months in the refrigerator once removed from the packaging.  The larger the chunk, the longer it will last.  If mold forms on the outside, simply cut it off and continue using.  There is no reason to throw-away good parmesan.