So which type of Polaroid material will be the best keeper over the long haul?

Estimate how many years out-of-date you could still use it?

What are the optimal storage conditions?

Of the 4x5 (545 holder) B&W materials, which one will be the best keeper? 52 or 54 or ?

What's the most out of date Polaroid you've used and still gotten good results?

And what qualities does it loose the most with age? Consistency, speed, evenness, or what?

We could start a pool to see who can make the best Polaroid in 2013 or so...