BRU suits a regional trip beginning near Brussels. If the first nights are in the city, compare collecting after that stay.
The airport places car rental desks on the left side of the Arrivals Hall. Follow the supplier’s instructions from the desk to the vehicle; an off-airport offer can use a different arrangement.
A car is useful for an Ardennes itinerary, rural guesthouses and stops outside the main railway network. For Brussels, Bruges, Ghent and Antwerp city breaks, compare rail with a rental: parking and city access can outweigh the convenience of keeping a car throughout the stay.
Compare airport collection with a later collection if you start with a city stay. Include the transport to a different rental branch and any extra parking nights when comparing the total cost.