Hi Edna.  Is Seneca serious?  The difficulty of poverty is how narrow and how real its dictate, a hyper-real state of utter, and utterly personal disillusionment.  The last, single, black potato on your plate, your inability to ignore how mean yet how valuable, how crucially you need the despised thing.

If you're a rich person and have the maid dish out that single potato for dinner, tell you that it’s your last, while you yourself know differently, having paid good money for tomorrow’s steaks, how prepared would that leave you for poverty?  No matter how good you play at poverty part of you is the conscious director who can never be prepared when real, inescapable, humiliating poverty shows up for dinner.

I’m not too convinced about the analogy of practicing on difficult musical scores in order to be prepared for the performance, not in the context Seneca speaks of.  Doesn’t he speak of negative capability?  As when you show up on opening night and not a single person shows up to hear you.  Becoming skilled musically would be of no help at all.

Leaving Seneca aside, Edna, as a practical, everyday matter poverty is the foundational state of sanity.  Each layer of abundance must be chosen carefully and adopted with caution.  As an artist you have to know that.  An excessive life stands a good chance of losing track of talent, the artist practicing where there is insufficient poverty, the riches, even subjective ones, crowding out genius.

As for any looming economic disaster, the best preparation would be an activism to insure that the rich suffer as much as any other.

Pardon me, Edna.  Can I add a couple of more thoughts?  I was washing dishes and my blood became hotter than the water.  Can you imagine?  Here's Nero's favorite PRETENDING to be poor!  What an affront to people in inescapable poverty the world over!  Phooey...

And more positively, when you and your family have your last potatos before you it is your privilage to under go the following transformation:  You must change (become divine) by yourself transforming the despised root.  By eating your last food with even joy and reverence it changes into a something divine, a food so divine to be forbidden to any one less rich and capable inwardly..

I think it is good to prepare for poverty in that you should not take wealth for granted.  It can be stripped from you so easily and in so many ways, as so many found out recently, to their continuing despair. 
 
Spend frugally, generally.  Invest wisely.  Particularly invest in yourself, in skills that can be of use to yourself and your fellow men and women.  Have a plan - how to downsize without discarding assets.  How to protect the assets you have.  Just some of the things that come to mind.  Always have a plan B, so when a crunch comes there are effective measures you can take to protect life, limb and property, notably your own, but also where possible, others'. 
 
All of which sounds terribly glib and is unlikely to fully protect one in times of attrition.  But even a bad plan is better than no plan at all.