During recovery, what must technicians do to ensure the safety and compliance with regulations?

To ensure safety and compliance with regulations during the recovery of refrigerants, it is crucial for technicians to monitor refrigerant pressure constantly. This practice allows technicians to maintain awareness of the system's performance and identify any potential issues, such as leaks or irregularities in pressure that could indicate unsafe conditions. Monitoring pressure facilitates effective recovery procedures, ensuring that the refrigerant is being removed efficiently and safely, while adhering to environmental regulations designed to minimize atmospheric contamination.

The other options do not align with safe and compliant recovery practices. Using recovery equipment that is not certified poses safety risks and can lead to non-compliance with legal standards. Recovering refrigerant quickly without checking for leaks disregards the important safety measure of ensuring that no contaminants are being released into the environment. Changing refrigerants frequently does not inherently connect to safety in recovery practices and may imply unnecessary wastefulness or improper handling of refrigerants, which contradicts environmental protection goals.