Depending on specific project goals and requests, the customer chooses the most appropriate option. 

Time & Material is used in the case when it is impossible to determine the full scope of work or the deadlines for their implementation before the start of the project. The client pays for the actually realized tasks within the project in accordance with the time spent. 

Fixed Price. For guaranteed predictability of costs and schedule. This model is used in projects where all stages of work, results, deadlines and costs are determined in advance and fixed in the contract. This approach allows reducing project risks due to a more accurate assessment of requirements.

Participation in the project under this model of cooperation implies the work of a particular developer or a team of developers. In this case, engineers are in full direct management of the Onsite PM. 

The customer is responsible for ensuring the workload of staff for the hours specified in the Work Order as the team is not involved in performing third-party projects and tasks.