Why not always configure for max number of event hub partitions?
The Azure Event Hubs overview article states the following: The number of partitions is specified at the Event Hub creation time and must be between 8 and 32. Partitions are a data organization mechanism and are more related to the degree of downstream parallelism required in consuming applications than to Event Hubs throughput. This makes the choice of the number of partitions in an Event Hub directly related to the number of concurrent readers you expect to have. After Event Hub creation, the partition count is not changeable; you should consider this number in terms of long-term expected