What type of fee structure is commonly employed for ongoing projects rather than one-time engagements?

The most appropriate fee structure for ongoing projects is the professional fee plus expenses. This approach allows for flexibility and adaptability in billing, reflecting the dynamic nature of long-term engagements.

In ongoing projects, the work can vary significantly over time due to evolving requirements, which makes a fixed fee or lump sum less suitable since it does not account for changes in scope or additional work that may arise. The professional fee component provides a base rate for the services provided, while the expenses component allows for the reimbursement of costs incurred during the project, which can fluctuate.

This structure ensures that the service provider is fairly compensated for both their time and any additional costs required to complete the project successfully, accommodating the continuum of services typically involved in ongoing engagements. Such a setup also promotes transparency, as clients are aware of the professional fees and expenses they will incur as the project progresses.