CQ (Charge of Quarters) CQ shifts rotate throughout the entire company, with just two Soldier's, 1 Non Commissioned Officer (NCO-E-5 and above) and 1 lower enlisted (E-4 and below) from the company per shift. CQ usually lasts 24 hours/Regular Duty Station.
12 hours for Basic Training/AIT
The Charge of Quarters is the responsibility of the NCO, and the lower enlisted is the runner, meaning that they perform tasks for the CQ.
The NCO and the runner, both may perform certain duties during their shift, ex: cleaning common areas, restrooms, and various other tasks. But they are usually tasked with answering the phone at the CQ desk, and doing random barracks checks.