It's difficult to answer this question without knowing just about everything about your hair and your past haircare routines.  For instance, if you've been using 'cones for a long time and don't regularly clarify, it will take longer for all the silicone buildup to be removed.  If you don't use a lot of 'cones or haven't been using them for very long, then it's probably more likely that you are instead preventing detrimental effects rather than trying to repair them. 

I used Pantene for *years*... MANY years.  I thought my hair absolutely loved silicones, it was always very smooth and shiny (in fact, if you look at my picture on the Ultimate Guide to Growing Long Hair, you'll see my hair in the midst of my "Pantene period."  But I also had a lot of knots, especially at the hairline underneath.  I had them so badly that it got to the point that I changed my mind about trying to reach my terminal length (or my knees, whichever happened first), and immediately cut 7" off my hair.  Then I decided to do some experimenting with non silicone products.  Guess what?  The knots I'd struggled with, litterally for years, all but disappeared.  My hair didn't get any less shiny but it's much easier to comb, even if I put it up in a bun for a couple days (which would have previously resulted in major knots).  I also notice that my hair doesn't get that "dirty" feeling as quickly (I'm not referring to oily hair, which I have and does not seem to be affected either way by 'cones... just the dirty "buildup" type feeling). Now I'm back on track to attempt terminal length.

I guess what I'm trying to say is it's all an experiment.  Avoid 'cones and see what effects it has on your hair.  You may be surprised at the positive changes that occur, or you may find that using some 'cones on your hair and clarifying regularly is the way to go.  Just be sure to give it enough time to make an educated decision about your results and how 'cones affect *you*!