What must be done when serving alcohol to ensure compliance with laws?

When serving alcohol, checking identification is crucial for ensuring compliance with laws related to age restrictions. This practice helps to verify that customers are of legal drinking age, which varies by jurisdiction but typically requires that individuals be at least 21 years old in the United States. By diligently checking IDs, bartenders and servers fulfill their legal obligations and help prevent underage drinking, thereby reducing the potential for fines, legal consequences, and harm to minors.

The other options, while they may be related to operating a bar, do not directly address the legal requirements around the serving of alcohol. Limiting drink selection does not impact age verification. Charging higher prices may affect customer choices but does not ensure compliance with age restrictions. Offering free samples, while a common marketing tactic, doesn't address age verification and could inadvertently lead to serving underage patrons if proper ID checks are not conducted.