well i sent out almost all of my secondaries in august, but i wasn't complete until november because that's when they received my mcat scores.
the only secondaries i sent later were to touro-ny and dcom in the first week of january because i was getting worried and thought adding a few new schools would be a good idea.
some schools may get your app and then decide to put it on hold and offer you a later interview. this happened to me with pikeville, i was complete there in the fall, but didn't get an interview from them until late jan. dcom said i was complete in january and didn't offer me an interview until april.
if you do for any reason get put on hold (for grades, new mcat score, whatever the reason may be), stay vigilant! i called/emailed the schools regularly and let them know i was interested. if it helps anyone, this is what i did for all of the schools i was put on hold at or waitlisted at:
1) i had a friend who attended the school write me a letter of recommendation because i knew her really well (some schools place more emphasis on this than others, but it can't hurt if you do know someone there)
2) sent in a letter of interest
3) sent 2 updated LORs from professors at grad school
4) submitted midterm grades and mailed an official transcript at the end of the semester
5) called here and there to let the admissions staff know i was still interested
6) submitted a new mcat score
if a school gets your app early and puts you on hold or if you get waitlisted, do whatever you can to get them to consider your app again soon.