Originally Posted by freecia

Tour Directors usually accompany the group's guests once they arrive at the airport in the destination country to their departure at the end of the trip. They're responsible for confirming detailed itinerary, setting the driving route with the driver, announcing how much time & where to meet the bus, chasing late guests, ensuring everyone is on the bus, arranging lodging keys, setting up morning wakeup & breakfast times, coordinating with meal stops (including dietary needs), explaining shopping, and taking care of guest needs (ie emergency medical). Decent ones will also explain the general history and significance, setup the itinerary well, inform of the next day's weather & itinerary, and know where the bathrooms are. Basically, they ride herd like a nanny or parent so the tour can progress in a timely manner without literally losing customers. And yes, it is actually a somewhat necessary role for most large groups of adults touring together.

Local guides are usually a day-of specific guide for a major city or attraction. They are the experts for local history, culture, and custom.

International Tour Directors for American tour companies usually expect a tip because that is the client base. Local guides go by the local tipping customs. This is based on my experiences on going on several bus tours in Asia & Europe.