Which type of services are good candidates for shared instances?

Shared instances in ArcGIS are optimized for situations where the services being used do not generate a high load on resources, as they can efficiently serve multiple requests concurrently. Infrequently used services are excellent candidates for shared instances because they typically do not require dedicated resources that would otherwise be allocated to more frequently accessed services. Since they are accessed less often, having them hosted in a shared environment allows for better resource allocation, preventing wastage on idle services.

This approach maximizes resource efficiency, particularly in scenarios where many different services might be less demanding on performance or might not need dedicated resources all the time. In contrast, frequently used services usually require more focused resources to handle the higher load, thereby making them less suited for shared instances. Services that do not require caching or non-map service types may be applicable in other contexts but do not represent the optimal scenario for shared instances in the way that infrequently used services do, as they may either have specific needs or workloads.