We did not feel the need because I knew or thought I knew where I wanted to apply. However there are little details that if you are applying to top schools you need to know and do not. Even if your GC knows, she may not think to tell you. For example, Michigan and the UCs treat an A- the same as an A+. I did not apply to Cal because was from OOS. Might have if I had realized I had a 4.0. We also missed a lot of merit deadlines and the Cal deadline, who knew it was in November. Would have loved a list on September 1. However the consultant will package you. If you do not want to be packaged or put on a strict timeline and made to feel bad if things are not done way ahead of time (I got every application on the deadline, not a minute before. January 1 was a lot of fun.) People in November were telling me I was totally going to miss everything and would never get it done.
As part of packaging there are tricks in terms of choosing majors that I did not know about and messed up, again did not want to be packaged. I want to be an engineer. I have no real idea what type. I have a little experience in one area, so I picked that. One school I did not choose CS because it had an extra essay. Stupid I realize but I honestly did not think it mattered. Meanwhile if I had picked French as my major I might have gotten into MiT (they want non science, who knew). I would hope a consultant can give you little hints like that. Apply as a physics major instead of CS because Penn needs more physics majors (making it up) assuming you can change later (again no idea). List your minor interest as geology or South African politics instead of economics. Instead I think I unversally applied for the most difficult programs possible and ended up being wait listed. The irony is that I am not even sure that I am more interested in those. They just sounded good. This tells me either that things are random or if I had made some minor tweaks things could have gone very differently, perhaps a consultant could have helped or maybe not.
I do think having someone look over essays is important. Yale’s web site even encourages you to show it to people to get help with grammar. It also prevents you from writing that hackneyed losing team sports essay that you thought was great or the essay about breaking your toe when you were 8 made you want to be a doctor. Cornell in their session asks you not to write about that.
I think the problem for most parents is by the time they really learn, all of their kids have gone to college.