Oldest blades you've ever shaved with?

I was wondering about how much the edge of a DE bade deteriorates in storage, and if this is even a valid concern - provided you're not storing your blades in the outdoor tool shed, under a damp rag or something silly.

So, purely out of interest:

• What was the oldest blade you've used, or are currently using?
• How was it stored?
• Did you notice any deterioration due to storage?

Oldest blades you've ever shaved with?