Each member of a family, apartment or house should have a personal kit readily available. This kit should sustain you for up to 72 hours, in the extreme event it takes that long for first responders to reach you.
A basic emergency supply kit could include:
Cell phone with charger, cables and an external battery to recharge your phone
Water, one gallon of water, per person, for at least three days, for drinking and sanitation
Food, at least a three day supply of non-perishable food
Medications, at least a three day of supply
Flashlight and extra batteries (cell phone flashlight can suffice so long as you have a means to recharge the battery)
First Aid Kit: For more information on building a First Aid Kit, go here
Whistle to signal help
Dust mask to help filter contaminated air and plastic sheeting and duct tape to shelter-in-place
Moist towelettes, toilet paper, garbage bags, and plastic ties for personal sanitation
Manual can opener for food
Local maps (ideally a digital map that resides on your phone, tablet or computer)
A backpack dedicated to this Kit
Twice a year replace the water, food, medications, batteries and other perishable items with fresh content. To help remember when to do this, schedule supply rotation for Daylight savings time, after you have replaced the batteries in your smoke detectors.