Scars from tummy tucks generally fall in the crease that forms in the lower abdomen when seated in a chair. The length of the scar, not surprisingly, is directly related to how much skin is to be removed. The more skin to be removed, the longer the scar. Attempts to really shorten the scar end up causing problems of pleating, irregularity, and "dog ears" (cone shaped prominence at the end of the scar). In most cases, the best results are obtained from using an adequate scar length, and, in my opinion, it is better to get a smooth shape rather than a shorter scar, all else being equal. A well placed longer scar is more acceptable than a shorter scar with suboptimal results! Hence the oft exclaimed saying "Shape Trumps Scar!" In plain English, getting a good shape is more important that getting a shorter scar, everytime!
Patients who have suboptimal results may have significant improvement of the overall results with a well executed scar revision (sometimes with a concurrent liposuction touch up). The timing and extent of your scar revision will depend on several factors which must be discussed with your surgeon.