I've rejected a job offer, In the future, if I want to move to their company, how long should I re-apply if I rejected their previous offer?
Did you actually tell them that you rejected their job offer, or that did you weren't taking it? Employers hire you because they need you not because they love you. If they advertise again for the same position, that's because they need someone. One advantage of having received a job offer recently is that you could point out to them that you went through the process successfully and hopefully, they remember you well enough to spare you from repeating the whole process. You could wait six months to a year but then, you'd have the start the whole process all over again. Choose your poison.