Why does Forrest always wear a blue shirt?

Question

From childhood to adult stage, Forrest Gump is always shown wearing a blue shirt.

Is there any reason?

Answer 1

According to Collider:

Have you ever watched the film and noticed that Forrest sports blue checkers a lot? This wasn’t due to laziness on the wardrobe team’s side; it symbolizes the many transitions in his life. He wears a different form of a blue checkered shirt in the first scene of each age transition in the film, to signify a change in time.

The movie ends with Forrest’s son similarly wearing a blue checkered shirt when he is getting onto the bus. Although the cast and crew from the film have not acknowledged why they did this, it became a fun Easter egg when it was discovered by fans.