http://en.wikipedia.org/wiki/Payment_card#Types
Its always a good idea to have enough cash in the bank, or somewhere else in the form of safe assets to cover all foreseeable monthly & annual expenses.
http://www.bargaineering.com/articles/cash-users.html,
http://jfmoneymatters.blogspot.ca/2012/03/digital-currency.html
Perhaps unless someone is among the very top wealthy people on the planet, its a good idea to spend less than what you have in total liquid assets.
http://jfmoneymatters.blogspot.ca/2013/01/the-frugal-way-way-of-big-money.html
There is an unsettling trend that has been unfolding over the past few decades. Eventually, almost every person & form of currency will be tracked in real time. Although there is an up side to this plan, there are also some eventual disturbing implications.
http://www.infowars.com/mccain-and-schumer-move-to-force-americans-to-use-biometric-id-for-employment
