The term "one size fits all" refers to the idea that one size of something would fit in all instances, and has been extended to mean one style or procedure would fit in all related applications.
The term has been in use for over 5 decades. There are both positive and negative uses of the phrase.

History of the phrase

The term "one size fits all" has been used as a common, cliche phrase for over 5 decades. It was already a popular term, in 1975, when Frank Zappa

Frank Zappa

Frank Vincent Zappa was an American composer, singer-songwriter, electric guitarist, record producer and film director. In a career spanning more than 30 years, Zappa wrote rock, jazz, orchestral and musique concrète works. He also directed feature-length films and music videos, and designed...

 recorded the album One Size Fits All

One Size Fits All

One Size Fits All is a 1975 rock album by Frank Zappa and The Mothers of Invention. It is the last Zappa album to be released with the subheading of "Mothers of Invention". A special four-channel Quadraphonic version of the album was prepared and advertised, but not released...

.

Positive views of the phrase

There are several positive views of the phrase "one size fits all":

• A wristwatch could be considered as fitting all people.
• In women's clothing, a flexible or open garment can be labeled as one-size-fits-all; however, the size is typically a medium size (able to expand), rather than actually fitting petite or extra-large (XL) sizes.
• A neck chain could be designed to be worn by men or women.
• Bicycle helmet
  Bicycle helmet
  A bicycle helmet is a helmet intended to be worn while riding a bicycle. They are designed to attenuate impacts to the skull of a cyclist in falls while minimizing side effects such as interference with peripheral vision...
  
  s with ring fit systems allow for a single size, also known as universal fit.
• In military gear, some items have just one size (but smaller or larger people have already been excluded from military service).

Negative views of the phrase

There are many negative views of the phrase "one size fits all" including:

• Many customers prefer to have custom-tailored clothing.
• Men's dress suit
  Suit (clothing)
  In clothing, a suit is a set of garments made from the same cloth, consisting of at least a jacket and trousers. Lounge suits are the most common style of Western suit, originating in the United Kingdom as country wear...
  
  s typically have specific sizes for chest & waist measurements.
• Shoes are an example where sizes (and widths) vary depending on the specific person.
• For the U.S. GI Bill in education, options and coverage will vary depending on each person.