I am not very good at this, but occasionally I do recognize a recycled costume- that is, a costume worn by a usually well known senior level skater that is being used by a younger skater(s) in a competition a few years later.
I went to see the JGP in 2001, and immediately recognized Yagudin's past costume on Andrei Griazev.
When I watched Petrova-Sikharulidze from roughly 1995, I recognized the costumes worn by Bechke & Petrov for their 1992 Olympics LP (The Nutcracker).
I had read that after Sergei's passing Katia had given away some of his costumes (probably hers too) to young pairs. I don't remember seeing them, but I am sure they were used in competitions by other skaters.