Systems and methods are described for allocating requests to implement new workloads within a dynamic set of servers. Existing load balancing techniques can result in “focus firing” on new servers added to the set, since a load balancer may view a new server as underloaded. With sufficient intensity, focus firing can result in overshooting target load for the new server, and the new server in fact becoming overloaded. The present disclosure modifies selection of servers as potential targets for a workload by at least partly biasing against selection of young servers. The bias imposed can be scaled to avoid overloading new servers.