It depends a lot on the school. Some schools will send the immediately after you're verified because the secondaries are available at that time (though most secondaries don't come out until July). Some schools send out secondaries in batches where only X number of applicants receive a secondary per day/week. For schools that screen their primary applications (University of Toledo, Wake Forest, University of North Carolina, Vanderbilt - just to name a few), getting a secondary can take significantly longer. You can check to the school specific threads for the schools in which you're interested to see when applicants started getting their secondaries last year - that should give you a rough idea of when to expect them.