Easily I would say that I could sustain us at least a yr, maybe longer in all aspects of our lives. Now, there are some things, like HBA, cleaners, etc. that would be at least 3 times that.
We are already in a recession and I think we are headed for another depression. I've been stockpiling food, diapers/pullups/wipes cleaners, hba, toiletries, vitamins/otc meds, powdered milk, baking goods, batteries, pet food (have like a 3 yrs supply) etc. in preparation. Maybe we won't and I'll just really be sitting at a great position and only have to buy perishables next year.

Who knows. We are also gardening w/my inlaws this summer and I am learning to can what we harvest for later on down the line. I also thank the good Lord that I live in a rural area and we have a means to hunt/fish and the necessary things to do that. We have also been buying ammo here and there as well.
I also have my kids in clothes/shoes/undies for at least the next 2 yrs. it's just something that i've always done since before they were born by shopping the clearances. And we have oil lamps and the oil for those too.
We also have camping supplies (like coleman stove, and propane for our gas grill, etc.) We also have a generator too. If all else fails, we'd build a fire to cook. If it got that bad, we would still survive. Wouldn't be the kind of eating that we're doing now, but we would eat and it would be mostly deer, rabbit, squirrel and fish.
And i know there are things that i am forgetting and it may sound a bit extreme, but honestly, this world that we live in scares the crap out of me. it is incredibly uncertain and i just feel that you can't be too prepared. in the event that nothing happens, well, these are all things that we use anyways, so i would just be more prepared for 2009-2010 and life would keep on rolling and we would just live off the stockpile.
Everything scares me half to death. Dh came home over a month ago talking about what he had overheard w/a possibility of the trucker's striking. That was enough to light a fire under me and make me start heavily getting my stockpile back and keeping it up. I've been buying even more metal shelves for my sunroom to store stuff on. And I need to go buy 2 more. LOL I just think that in today's time you just can't be "too prepared".