Yes, sishu7, it pretty much will.
What the admissions committee would like to see is a student who used his or her time wisely. Retaking an exam for which the initial results were very positive multiple times suggests the student is far more interested in the appearance of excellence than the actualizing of their potential. An EC in one's passion, I believe, will ALWAYS trump an SAT score improvement of a handful of points.
The point of the retakes, I think, is to eliminate any non-test variables. With the first exam, a lot of students underestimate the length of the exam, the variety of material covered, and their preparation for it. If they are not satisfied with their score, it makes sense to devote a little time to targeted studying and to retake the exam. If they feel they have to do this 3 or 4 times, particularly over a period of years -- maybe the room was too cold, maybe the student was ill one time, maybe they were just burned out -- and they can improve their score so doing, the admissions committee will not penalize you.
As others have aptly put before: there is no "they did this in one sitting! +50 points!" benefit to scoring well the first time, but there's no penalty for taking multiple sittings to do so.
Just use common sense, as Xiggi said. There is no need to retake a 2390. There is no need to take the exam at every offered test date in your junior year. The exam is ONE datum that the committee uses to determine admissions, and unless you're aiming for a school which has very specific cut-offs AND you think you could achieve them with a little practice, taking the exam multiple times and increasing your score by maybe 30-60 points is not going to help you nearly enough to justify the hours spent prepping for and taking it.