6 years and still good! in that case mine should be just fine as they have been in the fridge for 2 years. There is only about 1cc left in each syringe, so what I was thinking of doing is fill the syringes back up with distilled water. It should work fine since there appears to be plenty of spores in the 1cc of solution. If you can see a clump of them then that should be enough to make a full 10cc syringe, correct? If I can remember correctly you don't even have to be able to see the spores in the solution for it to be a good spore solution.