Thanks for all of the thoughtful replies. I am going to be revising my "roll" as time and finances permit.
As an aside, I was talking about this with my Dad, and he objected on the grounds that $500, in the bank, would earn me X-amount of interest by the end of the year. But after I explained to him what the lack of electricity does to modern banks, I think the lightbulb went off over his head, too.