It varies a little bit depending on which Immigration Appeal Division (IAD) office handles the appeal request, but from the time that your sponsor first files the request for an appeal until the time that you're actually scheduled for an Alternative Dispute Resolution hearing is usually about a year. If your case is not "allowed" at the ADR, your sponsor has the option to abandon the appeal, or wait for a date for a full hearing. On average the full hearing takes an additional year. If you're lucky enough to get a full appeal hearing to start with, it will probably be a little over a year - but I think they try to run most "non-genuine relationship" cases through the ADR process first.