3 11. The reasonable time for the conduct of a proceeding, the carrying out of an action or the issuance of an order is a frequently issue dealt with in the case-law of the Court. The Tribunal has made progress in regards to the reasonable term, admitting the information provided for by the European case-law- complexity of the matter, procedural behavior of the interested party (without placing the burden on it, of course, for the responsibility of the delays or the hindrance in the use of legal means of defense) and the behavior of the authorities (legal or of other nature). The Court added a new reference to all that, to which I referred on previous occasions: the consideration of the way in which the lapse of time affects the right in question. 12. The Court has not encoded the issue of reasonable time only based on the time elapsed – days, months or years-, considered in isolation. It is relevant to consider the fact on the basis of the characteristics of the matter subjected to the proceeding or decision. From here that, in several cases, including the instant case, the Tribunal expressly associates the reference to such temporal measurement with the material characteristics. Only in this way could we appreciate whether the elapsed time is reasonable or not. Evidently, in some cases, it is easy to note that a certain period of time for the processing of a case is, clearly, excessive; especially, if we try to ponder a proceeding that should be, by definition, simple and prompt, as required, for example, by Article 25 of the American Convention. When this is verified with simplicity, it is noted by the Court. In many cases, it is easy to note the need for States to reexamine the procedural regulation and material application of those means of defense in order for them to truly correspond to the provisions and purpose of Article 25. IV. Acquisition of rights 13. It is relevant to specify, so as to decide about certain violations, when one person has "acquired" certain right, which must be recognized, respected and guaranteed by the national government. Of course, I do not intend to reconsider the old doctrine of acquired rights and legitimate expectations, but to define, without loosing sight of the matter that I now examine, which are the legal situations from which the entitlement to a right derives that, as from such situations, such right may be claimed by an individual who “acquires” it and must be recognized and protected by the State. 14. To this end, it is necessary to consider- as has been done in the Judgment to which this opinion refers- the legal or procedural system that constitutes the legal ground, by means of general rules that determine broad situations, such as the particular action of the application of such system that recognizes or attributes the right to an individual who satisfies the conditions provided for in the rule. As from this double verification- that is, necessarily, among the facts of a contentious case of this kind- it will be possible to establish that the individual has turned into the person entitled to such right- for example, the right to property- whose violation entails the State's responsibility. V. Progressive development of economic, social and cultural rights 15. The victims’ representative gave rise to the consideration of the Court regarding the progressive development of economic, social and cultural rights, as from the change of the contributions covered to them and derived from the services