I have little to offer to the many good replies but this; MAKE FRIENDS!
I've been 3 decades out of San Francisco.I still keep in touch with a chinese kid i did a rather off the record favour for in bootcamp.
The people in Herman's deli on Geary remember me, as does the owner of Cable Car Clothiers and City Lights Bookstore.
The ladies on lake Mac Arthrur have probably all passed, but the black jazz club still sends me fliers for concerts.
When the Mafia Don I met at a deli passed away I sent a condolence card- and a thankyou note from his bodyguard!
You're in a unique, multicultural city within small geographical boundaries, the ones our grandparents grew up in back east.
So make friends there. In a disaster a known face is worth more than all the bartering bricks of .22s money can buy.