From an e-mail discussion with experts in the .NET User Group:

According to the specification, the client should complete paused browse operations before starting new ones to avoid the BadContinuationPointInvalid StatusCode. So, it should first call BrowseNext before making another Browse request. Since the client cannot know in advance whether a BrowseService Call requires continuation points, it can only achieve this by:

• Managing potentially reserved continuation points on the server (if it is multithreading capable, this can be quite complex and error-prone).
• Executing a maximum number of BrowseServiceCalls overall, based on the server’s available continuation points. In other words, the client should reserve continuation points client-side not only when it receives them from the server but also when it initiates a ServiceCall that might require continuation points.

An additional complication arises from OperationLimits. If the client wants to browse many nodes simultaneously, but the server limits the maximum number of nodes per BrowseService Call, the client must consider the continuation point restrictions during packaging."