Three factors matter: the language combination, the subject field, and the mode of interpreting. Interpreters work from and into specific languages, and the topic determines whether legal, medical, technical or financial expertise is needed — specialist terminology cannot be improvised on the spot. It also matters whether the assignment is a plenary session, a guided tour or a closed meeting, since each calls for a different mode and different equipment. At conferences, interpreters and technology are usually arranged as a single package, so that the system, the number of booths and the language allocation all line up.

In simultaneous interpreting, the interpreter translates almost at the same time as the speaker from a booth, allowing the programme to run at normal pace; this is the standard at conferences. In consecutive interpreting, the interpreter waits until the speaker finishes a passage and then translates, which roughly doubles speaking time but requires little equipment. Whispered interpreting is a light form of simultaneous interpreting for one or a few people, optionally using a tour guide set. The choice directly affects planning: consecutive interpreting means building extra time into the programme.

Preparation is a substantial part of the work, so the earlier the material is available, the better the result. Useful documents include the programme with timings, the presentations, speaker names and job titles, previous minutes, and a list of technical terms, abbreviations and product names. If a text will be read aloud or a video shown, it is important to share it beforehand, because read-out text is delivered faster than spontaneous speech. Confidential material can be shared without concern: interpreters are bound by professional confidentiality.

Pricing is driven mainly by the number of languages, the length of the programme and the mode of interpreting. Because simultaneous interpreting is done in pairs, two interpreters per language are usually assigned once a session runs longer than about an hour. Travel time, any overnight stay, preparation time and the required equipment — booths, channels and receivers — also feed into the quotation. Cancellation terms form part of the agreement as well, since interpreters block out a day or half-day that cannot be reassigned.

A sworn interpreter is listed in the Dutch Register of Sworn Interpreters and Translators (Rbtv) and is mandatory for certain official proceedings, such as court hearings, police interviews, notarial deeds and immigration procedures. For conferences, presentations and corporate events, sworn status is not required; there, subject expertise and conference experience count for more. That said, arbitration hearings, tribunals and legally sensitive meetings often deliberately use a sworn or legally specialised interpreter. When in doubt, it is advisable to check the requirement in advance with the organising or receiving authority.