If you want to build up your career as a good simultaneous interpreter, knowing two different languages is not adequate. In fact, it is equally important that the interpreter is proficient about the subject matter. How much time is sufficient to get ready for a simultaneous interpretation assignment may vary from individual to individual.
Say an interpreter has two different simultaneous interpretation assignments on the same day, one from eight in the morning to noon and another from two in the afternoon to six pm. There will be various factors that will determine how much time an interpreter will require getting ready for a meeting. These factors may include the total time for preparation, whether they already have some knowledge of the topic, how responsible they are and so on.
It is extremely crucial for a simultaneous interpreter to have existing knowledge of the conference or the topic so that they can perform well. Merely knowing the topics of the day will not suffice; they should be prepared with the vocabulary of every individual event. After all, there is always a possibility that certain terms may pop up in the event, which may not be present even in the source language. The client or the employers also expect that their simultaneous interpreters only speak about matters they are familiar or proficient about. An interpreter can get ready by making use of documents and speeches for a particular meeting, specialized journals, newspapers, the Internet and so on.