Question: If I'm making Homemade Jams/Preserves, how long will they last?

Answer: 
The [Good Eats jam episode](http://www.goodeatsfanpage.com/Season2/Jam/JamTranscript.htm) suggests 2-3 weeks if you don't actually preserve the jam in a home-canning kind of way and about a year if you do.
Home made Jam made with half Fruit and half Sugar will last almost indefinitely... it's additives that spoil food, placed into in a sterile jam jar it could be there many years and still as good as the one eaten in the first week, Ask your granny not a jobsworth! 50/50 nothing else!