Here is my video on every reused costume on Dance Moms. I am going through each season, so this video is just season 1 only.

Introduction - 0:00
Episode 2, "Wildly Inappropriate" - 0:06
Episode 3, "Cheerleader Blues" - 0:46
Episode 4, "Stealing the Show" - 1:27
Episode 6, "Dying to Dance" - 3:24
Episode 9, "From Ballerinas to Showgirls" - 3:45
Episode 10, "Cathy Brings It On!" - 4:07
Episode 11, "It All Ends Here" - 4:48