From what is possibly the best personal finance/investing book of all time, Gerald M. Loeb's "The Battle For Investment Survival":
...If there is an effective hedge against calamity, it is a combination of geographic diversification, retention of capital in mobile form and the keeping in personal touch with active businesses, both at home and in other centers.
One must keep personally alert, active and in the swim. Retired businessmen, in my opinion haven't much chance. One must not tie up all one's assets in one's home town or in a form that is not liquid and subject to easy shifts. There are far too many people who have a small business in their home city, their own house in the same city, and if they own any securities, some shares perhaps of the local utility company.
In addition their friends and connections are all in a radius of 10 to 15 miles.
My real thought is that one's greatest assets are his mental competence to do something useful and his connections.
Therefore establish some emergency connections away from home. Establish a fund or funds away from home as well, both as a "calamity hoard" and as an aid to keeping your foreign interests alive....
...One ought to be able to move to several parts of this country and the world, and have enough friends to be happy and get a helping hand to start, and have ready at hand enough funds for a grubstake to start.
Ask yourself how many widely separated places you could go to and make a successful new start in life....
Excerpted from Chapter 29, "Travel as an Education for Investors" of Gerald M. Loeb's The Battle For Investment Survival, Simon & Schuster, 1935.
Considering what was going on in Germany at the time, and about to engulf all of Europe, it was pretty good advice.
What you don't want is to be the Detroit pharmacist with his home and business in the city along with a small income property and maybe some stock in the local electric utility, The Detroit Edison Company (now DTE).
See also:
Happy 75th Anniversary to one of the few MUST READ Investing Books: Gerald M. Loeb's "The Battle for Investment Survival" Chapters 1-3"Gerald Loeb's Strategies For Winning On Wall Street Still Ring True"
Ken Fisher's Forward to Gerald Loeb's The Battle For Investment Survival
"How the Superrich Hedge Their Bets"