When taking on interpreting work, I always ask the client to supply as much background information about the assignment as possible. This enables me to prepare beforehand by doing background reading, checking out essential terminology and so on.
For short consecutive interpreting jobs, an hourly rate normally applies, based on the total number of hours required for the actual interpreting and for preparations, travel and any waiting time.
For conference and other simultaneous interpreting, rates are calculated per day or half-day. These rates include preparation time and up to three hours of travelling time.
Any travel, subsistence and/or accommodation expenses will be charged in addition to these rates.
I will happily supply an estimate for a specific assignment on request.