That would be up to 12 years after the individual receive notice of its date of separation from active military service or its first VA service-connected disability rating.
Umm, o.k. at least is a reasonable period. Now, can you tell which are the requirements for VR&E if someone still on active duty?
That person is already having 20% or higher pre-discharge disability rating? Will he or she leaving soon the military?
That's correct in both questions, yes.