Smart Cards reliability is a complex topic.  All manufacturers warrant that their products will pass the ISO reliability tests, however these test conditions are meant to simulate "real life" conditions.  Unfortunately, every project has different terminals, software, environmental conditions, and usage patterns.  Additionally, as more features are added to the card (magnetic stripe, photo image, smart card chip, embossing, surface printing, proximity technology), it only takes one element to fail for the card to be considered "bad."  Therefore, predicting card reliability is never easy. 

There are many potential sources of card failure from bugs in terminal software, to inappropriate terminal mechanical elements, inappropriate user actions (e.g. folding the cards, sticking them to the refrigerator door with a magnet, scraping ice off the car windshield, jimmying a door).  In fact, a whole book could be written on inventive uses of cards.  Unfortunately, for what ever reason a card fails, the user will state "it just stopped working" and request a replacement.  Therefore, its important to plan for this event. 

The good news is that smart cards are quite reliable as the industry has been making billions of cards per year and has leveraged experience from traditional from magnetic striped cards.  Below is a card failure chart from one of the oldest and largest bank smart card projects in the world, the French GE Carte Bancaire project.  This project has more than 22 million Visa Debit Smart Cards in use and more than a decade of experience. 

Graphic courtesy Schlumberger and GE Carte Bancaire - 

A few key suggestions/comments which all should consider when starting a project.

	The failure rate of the cards typically is higher at the start of the project, for a number of reasons.  Therefore, provide a method to track where the card worked last.  It is important to identify bad terminals, bad terminal software, or other potential sources of failure.  One "bad" device in a system can damage a lot of cards.
	Cardholder education is important.  Informing the card holder about the card care is always a good idea.  In one university project, a student punched a hole in the card exactly where the chip thinking it was a punch hole indicator.
	Plan for the card to be lost, stolen, misused, and damaged.  Clearly state the card replacement policies and implement a process that quickly puts a working card back into the field.