One of the built-in services Apple offers application developers in OS X is a method for listing recent documents that have been opened by that particular application. When implemented, you will see an "Open Recent" option in the File menu of the respective program. This feature can be exceptionally useful; however, there are times when the default number of items listed is not enough.
Some applications contain a preference setting for the number of recently used items, but others just use the default value of 10 items. To change this number, just enter the following command in the Terminal:
defaults write APPLICATION_DOMAIN NSRecentDocumentsLimit NUMBER
In this command, the "APPLICATION_DOMAIN" is usually the first part of an application's preference file name, such as "com.apple.TextEdit" for the TextEdit application. Change "NUMBER" to the desired number of recent items to list, and press enter. You should not have to supply a password for this to work, and the settings will be saved in the designated application's preferences file for the current user only.
Keep in mind that some applications have their own methods for implementing a Recent Items list, so this may not work in all situations; however, it is worth a shot. I regularly use TextEdit, and expanding the number of recent items to 25 has helped.