It helps when deciding how many troops to send to the service.
Tribal Calculator assists in deciding how many troops to send to the service.
Before using send explorer to the target village, from the information the report contain feed the gaps in the application and you will have how much of light cavalry or lancers will be required to plunder the village successfully.
Remember that depending on the target village defense, there may be casualties in your troop, which may necessitate a larger troop shipment, but generally in barbarian villages there is not much defense.