We adapt to new languages and systems in stride, without significant schedule impact. This is the approach to take when the delivered result is more important than the avoidance of learning curve. A contractor should be expected to seamlessly become part of a project team to be managed the same way as the entire team. Every technical worker has unique skills and interests. Whether contractor or regular employee, a technical worker performs best when working in areas where they are skilled and enthusiastic.
Good assignments mean good teams, good products, and good value.
The use of contractors allows the client increased flexibility in forming project teams. A contractor is only costing money when actively working and can be readily let go between projects in order to protect the integrity of the organization's core team. Also, a person who is able to make a living at independent contracting is likely to be a go-getter who is used to making a success out of project assignments. Successful companies include one or two contractors in each development team. One possible rule of thumb might be to engage one contractor for every four direct employees.