I always check the household goods dropped off at the local landfill when I'm there dumping stuff from my projects. Here's an unopened container of liquid fertilizer concentrate I recently scored.....of 'historical' value, due to it's 1988 vintage.
I'm sure the product is still good, because it's unopened and it's still entirely in liquid form. Sometimes when liquid chemicals get old they form solids and then the stuff is kaput.
The 12-6-6 analysis is a fairly popular one and because of the liquid formulation, I will probably just use it for my foliage plants.