Depends on: the number of cracked ribs; the severity of injury--cracks with splinters, vertical vs horizontal; location--like around the sternum, spine, or sides; and the age and general health of the patient.
My Dad once hugged my grandma (then 60ish) so tight he cracked a couple ribs on her--took 2-3 weeks to heal with light painkillers, rest and no binding.
More severe cracked ribs could involve 2-3 weeks of bed rest, like a wide ace bandage wrap, and physical therapy to overcome the debilitating effect of bed rest.