A recent question from a good friend about food storage inspired me to try to find a Food Storage Calculator. This link is the best one I have found so far. You can input your family numbers and it automatically calculates a list of what you would need in your pantry, as for staples for your family for a whole year! In my opinion it is not complete - however it is the best one I have seen yet! (Let me know in the comments if you know of a better one please!) We don't use some of thier things (like corn syrup for instance) but I intend to alter it using the things we do use and use it to measure the condition of my pantry stock so I may make adjustments as needed. I think my goal will be to add 50% to this, because we eat out of our pantry and we serve lots of people as our home lends itself to lots of hospitality. This will give some wiggle room for restocking as well. Serving others and hospitality will not change in hard times - in fact it is likely to increase for us! A year is a very realistic time frame to plan one's pantry around, if you think about it. It will take you through every season of the year and give you time to replenish livestock, hunting or gardens. If one were only to have 3-6 months of stock - and your need are longer or fall "off season" you may not have time to grow more food or meat/dairy.
Here also is a wonderful list of things from the Prudent Homemaker on stocking one's pantry. It is where I found the link above. I am feeling a need to revamp my inventory system too. As soon as we get moved into the new roots cellar...I think that will be added to my to-do list. :-)