3liza:

Year-by-year tracking of corset shapes in the first two decades of the 20th century, which is an excellent thing to learn for the purpose of:
Dating historical art and photography (thereby helping you learn what to apply from it to your own work)
Design period-accurate costumes for your characters
Gaining a better understanding of the stylistic zeitgeist of any particular year.  Shapes, colors, and forms are echoed through every aspect of an era; what people were wearing directly corresponds to what they were building, painting, riding in, and talking about.

3liza:

Year-by-year tracking of corset shapes in the first two decades of the 20th century, which is an excellent thing to learn for the purpose of:

  1. Dating historical art and photography (thereby helping you learn what to apply from it to your own work)
  2. Design period-accurate costumes for your characters
  3. Gaining a better understanding of the stylistic zeitgeist of any particular year.  Shapes, colors, and forms are echoed through every aspect of an era; what people were wearing directly corresponds to what they were building, painting, riding in, and talking about.