The Library of Congress might talk about its 235 terabytes of data, but some U.S. companies already have it beat—try petabytes, literally thousands of terabytes of data. If your company has more than 1,000 employees, you're no doubt in the petabyte world. As the cost of servers and digital memory decreases, the amount of data created and stored by businesses increases at staggering rates.

Lots of data can mean only one thing when it comes to litigation: crippling discovery costs. One of the leading document review tools had a 100 percent increase in the number of documents hosted from 2010 to 2011, from fewer than 5 billion to nearly 10 billion. When faced with this explosion of electronic data, your first and best line of defense in limiting discovery costs is having a well-drafted document retention policy and following it to the letter.

Elements of a good document retention policy