I have two 72-hour BOB's (Bug Out Bags) in different locations, plus a stockpile of food and supplies to go for (hopefully) a year. Water is the hardest since you need a minimum of 1 gallon/day per person just to consume and it does not store for long periods without going stale. I have a specially ordered water tank that fits in a bathtub that will hold 100 gallons and can be filled in less than 20 minutes.
For the 3-day kits, packets of water were made with FoodSaver bags (sealed only) since they are very flexible, some high energy protein foods, first aid supplies, change of clothes, shoes, foul weather gear, crank radio/flashlight, rope, knife, matches, candle, 2-wheel radios if more than one of you.
The stockpile is just excesses of what is used normally in the household and is rotated so everything remains as fresh as possible. I 'can' a lot of food which helps also. Things like Toilet Paper get stored in those blanket bags that you can seal with your vacuum so it doesn't deteriorate over time.
One thing many people forget to put with their disaster supplies is a 'church key', aka can and bottle openers. Canned goods galore and nothing to open them with.