The best event partners can clearly explain which services they manage directly and which ones they outsource.
This matters because in-house capabilities usually improve quality control, communication, and speed of problem solving. For example, if a company manages design, staging, AV, production, printing, or show calling internally, there are fewer delays and fewer layers of coordination.
Ask for a clear list of services. A reliable event planner should be able to explain exactly what they can do for conference production, stage setup, event graphics, technical support, and event management.