What is the purpose of a Pocket Protector?

A pocket protector is a small, typically rectangular sleeve made from materials like plastic or vinyl, designed to be inserted into a shirt or jacket pocket. Its main purpose is to protect the pocket from stains, wear, or damage, especially from ink leaks or the sharp points of pens and other writing instruments.

Historically, and even today for some, pens (especially fountain pens) were prone to leaking ink. A pocket protector acts as a barrier, preventing ink from bleeding through the fabric and ruining the shirt. They also help to keep the pocket from stretching out or tearing from repeated insertion and removal of pens, pencils and other items.

Pocket Protectors serve several key functions:

Protection: They shield the fabric of the pocket from being marked, torn, or soiled by pens, pencils, and similar items. This was particularly important when ink pens, which were prone to leaking, were widely used. 

Organization: They provide a convenient way to carry and organize multiple writing instruments and small tools, keeping them easily accessible and preventing them from shifting or falling out. 

Durability: The pocket protector also helps prevent the pocket itself from wearing out due to repeated insertion and removal of pens and other objects.

Originally popular among engineers, students, and professionals who frequently carried pens, pocket protectors became associated with "nerd" or "geek" stereotypes due to their practicality and visibility in technical fields. 

While their use has declined with the advent of less leaky pens and the shift to digital devices, they remain a symbol of practicality and organization in professional and academic settings.