38 CFR 21.5041: Periods of entitlement.

(a) Ten-year delimiting period. Except as provided in § 21.5042 no educational assistance shall be afforded an eligible individual under chapter 32 beyond the date of 10 years after the later of the following:

(1) His or her last discharge or release from a period of active duty of 90 days or more of continuous service; or

(2) His or her last discharge or release from a period of active duty of any length when the eligible individual is discharged or released—

(i) For a service-connected disability;

(ii) For a medical condition which preexisted such service and which VA determines is not service-connected;

(iii) For hardship; or

(iv) Involuntarily for convenience of the government after October 1, 1987, as a result of a reduction in force, as determined by the Secretary of the military department concerned in accordance with regulations prescribed by the Secretary of Defense or by the Secretary of Transportation with respect to the Coast Guard when it is not operating as a service in the Navy.

(b) Use of entitlement. The individual—

(1) May use his or her entitlement at anytime during the 10-year period after the last discharge or release from active duty or other period as provided pursuant to § 21.5042 of this part;

(2) Is not required to use his or her entitlement in consecutive months.