Let X be a Noetherian space, let f be a continuous self-map on X, let Y be a
closed subset of X, and let x be a point on X. We show that the set S
consisting of all nonnegative integers n such that f^n(x) is in Y is a union of
at most finitely many arithmetic progressions along with a set of Banach
density zero. In particular, we obtain that given any quasi-projective variety
X, any rational self-map map f on X, any subvariety Y of X, and any point x in
X whose orbit under f is in the domain of definition for f, the set S is a
finite union of arithmetic progressions together with a set of Banach density
zero. We prove a similar result for the backward orbit of a point