Section 407.4 - Basic requirements for entitlement(a) An individual must meet the following requirements to be entitled to SMI:(1)Eligibility. The individual must meet the eligibility requirements specified in § 407.10(a) .(2)Enrollment. The individual must enroll for SMI, or must be enrolled by a State under a buy-in agreement as specified in § 407.40 .(b) SMI pays only for covered expenses incurred during an individual's period of entitlement.