404.603—You must file an application to receive benefits.
In addition to meeting other requirements, you must file an application to become entitled to benefits. If you believe you may be entitled to benefits, you should file an application. Filing an application will—
(b)
Protect your entitlement to any benefits that may be payable for as many as 6 months or 12 months (depending on the type of benefit, as explained in § 404.621) before the application was filed; and