Plato, Laws 772b

καὶ πολλὰ νομοθέτην μὲν ἐκλείπειν, τοὺς δʼ ἐμπείρους ἀεὶ κατʼ ἐνιαυτὸν γιγνομένους αὐτῶν, ἀπὸ τῆς χρείας μανθάνοντας, τάττεσθαι καὶ ἐπανορθουμένους κινεῖν κατʼ ἐνιαυτόν, ἕως ἂν ὅρος ἱκανὸς δόξῃ τῶν τοιούτων νομίμων καὶ ἐπιτηδευμάτων γεγονέναι. χρόνος μὲν οὖν μέτριος ἅμα καὶ ἱκανὸς γίγνοιτʼ ἂν τῆς ἐμπειρίας δεκαετηρὶς θυσιῶν τε καὶ χορειῶν, ἐπὶ πάντα καὶ ἕκαστα ταχθείς, ζῶντος μὲν τοῦ τάξαντος νομοθέτου

and that rules and amendments should be made from year to year by those who have constant experience of them from year to year and are taught by practice, until it be decided that a satisfactory code has been made out to regulate all such proceedings. A fair and sufficient period to assign for such experimental work would be ten years, both for sacrifices and for dances in all their several details; each body of officials, acting in conjunction with the original lawgiver,