The guideline used to be have supplies sufficient to last three days in the case of a disaster. That was the typical time for government resources to have enough infrastructure repaired for people to be able to restock.
However, Irma caused so much havoc over so much of Florida that eight days later food and other consumables can't get to some areas and the inhabitants there can't travel far enough to reach a supply source. Some people are described as "scraping the bottoms of their cupboards."
Keep at least a week's worth of canned food on hand. It remains safe to eat indefinitely as long as the cans are not ruptured, bulged or rusted. Two weeks is better. You can cycle through your reserves to keep them fresh, or give stuff to food banks once it gets older than you like. Turn cans with liquids in them over twice a year to help maintain palatability.
Have a way to heat food which does not depend on your utilities. A camping stove is good, and these can often be found cheap at yard sales and such.
Learn how to use bleach to treat water for drinking and cooking. Have coffee filters on hand to remove silt and such before using the bleach.
Have at least one battery powered AM/FM/Weather radio with spare batteries. Have at least one flashlight for each person, also with spare batteries. There are actually radio-flashlight combinations with solar panels and generator cranks which can even charge cell phones. The Etón Scorpion II is a good example. Those aren't cheap, but could literally be lifesavers.
Keep the same two-week buffer for medications, vitamins and other such supplies.