S.C. Code Ann. § 50-23-370 – Expiration and renewal

(A) Except as otherwise provided, a certificate of number awarded pursuant to this chapter continues in effect for three years unless sooner terminated or discontinued in accordance with this chapter. Certificates of number may be renewed by the owner in the same manner provided for in the initial securing of the certificates. The department shall fix a day and month of the year on which certificates of number expire unless renewed pursuant to this chapter.
(B) A renewal application for a certificate of number, except those from marine dealers, presented after thirty days from its expiration date is subject to a late penalty of fifteen dollars.
A renewal application for a certificate of number presented after sixty days from its expiration date is subject to a late penalty of thirty dollars.