Although your posting preferences (role and location) will be met wherever possible, this must be balanced with organisational needs, so you may be required to fill an urgent, specialist or operational role regardless of your preference. Each Service has a career management branch through which your posting preferences, longer term career prospects and personal situation will be taken into consideration.
The posting cycle is generally every 2-3 years and you must be prepared to change jobs and/or location. Due to operational and administrative issues, there are times when postings will be cut short.
Depending on the length and location of the posting and your personal situation, you may choose not to move your family. If you post to a job away from your family in most circumstances the military will pay for you to travel home periodically.