can buffer ever go bad? - (Feb/21/2014 )

can phosphate buffered saline solution ever go bad (for reasons other than contamination)? for example, does it "expire" after a certain time period? or is it highly unlikely

Aside from contamination and precipitation, you should be fine.

I agree. The ingredients are quite stable (or have a high metastability as a chemist would call it) and can exist long under normal conditions.