Take your responsibility after end of use. Vehicles that no longer meet emission standards should not placed on the second-hand market for reuse, because the negative environmental impact of emissions will continue. It is better to aim at reuse of parts and recycling of valuable materials.
In case of leasing, ask for transparency about what happens to vehicles or parts (such as tires) after the leasing period.
Regular maintenance and repair can extend the life of the vehicles.
Eco-driving courses can reduce fuel consumption.
Check whether a car sharing and/or a smaller fleet can meet the needs. Make sure you have a good reservation and monitoring system.