Agreeing w/ Nicodemus....the ingredents are the key. I don't think there is a single easy ratio gaining "X" amount more time by using the long-term storage techniques. I'm pretty new to this myself, and have similar questions. It would be nice to steer clear of the things people have already found not worth the effort of repackaging.
Hopefully there are some folks that can give us some real experiences.
It is hard to pass up some deals for 10 for $10 on noodles and rice that take so little fuel to prepare. But, if they are rancid when we go to use them, what's the point? It would be nice to have a list of what is best to use, certain brands or flavors. Personally, I have stayed away from things that require milk to prepare (alfredo, "creamy" stuff)....but that is more a gut feeling, not an experience.
As a point of reference, at this very moment, I'm eating some Jiffy corn muffins I found in the back of the cupboard last night. They have been expired over two years (best used by Oct 2010). Normally, I'd have thrown them away, but I thought.."what the hell". Actually, I was sort of happy in a way, an oppertunity to test something, so I gave it a shot. They are a little dense, but taste OK. I bet if it were vacuum sealed and out of light...5+ more years? Longer?
Also, I found this website on another TSPF thread ....
http://www.stilltasty.com/. Folks out here are awesome!