Something often overlooked but very important to us older folks is a spare pair of glasses and a weeks worth of important meds.

An old Alice pack works for me others have already given their thoughts on what to include. Goggle is your friend just do a search for bug out bag and you will have weeks worth of reading just remember the contents for me will not be right for you and contents will be specific to your area. What I had in FL would not be of much use here in the north woods.

Think, water, shelter, food and communication along with what you need/ can legally have to defend yourself