geometric nonlinearity

When should I check the option of "geometric nonlinearity" ? I understand it is used for large deformations but what is meant by large deformation? What should the magnitude of a deformation be inorder to be classified as large deformation?

I am trying to model an artery and am applying some pressure to expand it. Do I need to select the geometric nonlinearity in my case?

Thanks for the help!

Sincerely,
Sirisha