It depends on what you intend to use these hops for. If purely for IBUs, calculators do a good job of showing you degradation over time (assuming cold stored, free from light, and air tight). If you want aroma/flavor character from the hops (0 minute/dry hop additions), I would smell the hops at the time you are intending to use them. If they don't smell fresh and have the character you're looking for, I'd toss them. I know, it feels like a waste to do that, but your beer (and those drinking it) will thank you for using fresh hops.