Given the state of affairs in the world, particularly here in Virginia, I have been thinking about having a few weeks to a month or so of emergency food on hand.
I'm going to go opposite from what most will tell you, but it's based on decades of living prepared to eat.
Sit down first and work out what you buy each week and each month in groceries for your normal daily eating.
Then clear out some shelf space and set up your pantry so you can put oldest stuff in the back, newest it the front.
Then slowly (or in a big lot if you want), buy more of what you eat every day till you have a full month work of your normal shelf stable groceries in the pantry.
Then go to your frozen foods, stock up a month worth of all the frozen stuff / meat stuff that you normally eat, and if needed get a chest freezer. Have a plan to have a small generator that can run it and fuel to keep it going. On a closed chest freezer, you'll only need to run it a couple hours a day to keep it cold if you are doing it right.
THEN take an inventory of what you buy that is not shelf stable & not frozen, such as milk/eggs/dairy/vegetables and the like, then go get the "survival" freeze dried versions of all those and stock them.
Then make sure you have all your household cleaning supplies, toilet paper, bleach, hand dishwashing soap, garbage bags and all that good for a month at least.
Then stockpile a bunch of water bottles, or something that is not too hard to rotate thorough, at least enough for a week, a month if you can, then also get a bunch of good water filtration systems.
Make sure you have candles / torches / small solar panels / generator & plenty of batteries as is best for your specific situation along with enough medical supplies for basic things that come up.
That right there will put you better off than 95% of the population in the country today.
Then if you want to go from there, start working on long term food that is canned / freeze dried or such based on what you and your family actually currently eat every day.
These folks have some pretty good options for very specific single ingredient storage:
https://www.thrivelife.com