Systems and methods for estimating the number of workers needed to perform a garbage collection operation are disclosed. Similarity groups are used to identify segments associated with objects in a computing system. Using deletion records that identify objects to be deleted, the similarity groups impacted by the deletion records can be identified. The number of workers can be determined based on the impacted similarity groups. More specifically, the number of impacted similarity groups and/or workers can be evaluated in terms of memory requirements, input/output constraints and/or time requirements to estimate the number or workers needed to clean similarity groups impacted by a garbage collection operation.