petitioner's voluntary retirement from service on 11.1.1996, the rules prevailing required 13 years of service for promotion to the post of Major. It is also undisputed that it was only in January, 2000 that the experience requirement was reduced from 13 years to 12½ years. That reduction was done by the Government of India by Annexure D order. When the reduction of experience was so ordered, unless the order so specifies, the benefit of the order can only be taken with prospective effect and it cannot be retrospective. Though it is true that the cut off date fixed cannot be arbitrary or irrational, when a new benefit is introduced by the Government of India and that too, involving financial consequences, it is always open to the Government to introduce the same with effect from a date decided by it. In so far as this particular case is concerned, 14.1.2000, the date on which the OM in question has been issued, is that date and therefore, cannot be said to be an irrational one justifying interference in the writ petition.