Take for example the "Minister" diary. A Minister in French would have a different script than a Minister in English. A 1999 Minister would have a different script than a 2000 Minister. A 1999 English Minister, customized for a client, would have a different script than a standard 1999 English Minister.
Of course, it seems logical that all the above scripts should be very similar apart from one or two details, such as the language or the year. That is indeed the case, and Q++Studio lets you easily reuse scripts.
See also: Script Structure.