There are differences in the types of nests and their locations but the premise behind the treatments is basically the same. Apply the chemical directly into the nest killing some of the colony on contact. The remaining bees or wasps are killed as they come back and track the poison throughout the nest, killing themselves and any remaining larvae. The nest may be left in place after treatment to help facilitate this process. That choice is made by the technician at the time of treatment.
Honey bees are the only bees that keep the same nest year to year.
All other wasps and bees make new nests each season. The bulk of the colony dies in the winter with just a few hibernating to come out next spring and rebuild their colony and nest. This is why it can be hard to find the nests in early spring. As the season progresses the nests grow in size and population, making them easier to find but also more dangerous to deal with. It is not uncommon for us to remove large nests from walls and ceilings after bees have broken through the sheetrock into the house.