The term “belt and suspenders” is an example of a metaphorical idiom; the meaning is that a person who “wears belt and suspenders” is very cautious. The idea is that a belt holds up a person’s pants, and that suspenders achieve same task. Using both, therefore, is seen as superfluous and unusual, leading to the use of the figurative phrase to describe someone who seems obsessed with safety, or overly careful about something.
This idiomatic phrasing varies between different English-speaking societies. The British version of this phrase is “belt and braces.” The American version, “belt and suspenders,” references a garment accessory that was once popular within the country, not only as a functional accessory for holding up pants, but more recently as something of a novelty fashion item. For example, restaurants and other businesses may use suspenders as part of the uniform, as part of visual “branding.”
Word experts trace the origin of the phrase to the mid 1900s. As suspenders become more and more obsolete in American society, this phrase is heard less and less. Today, it is not a very usual part of the language, but rather, something that may appear in older printed text, or perhaps with certain popular figures who might use them as a sort of trademark for their image.
Another way to refer to the idiomatic phrase “using belt and suspenders,” is the idea of “double insurance.” Those who are referring to this kind of concept will often use more technical language, such as “redundant safety measures.” An important difference is that, while “belt and suspenders” has the connotation of being superfluous, redundant safety measures are often a deliberate part of engineering, and a very important part of keeping individuals safe within a certain field or industry.
In modern times, government regulators in many countries around the world have been entrusted with enforcing practical and sometimes redundant safety measures. Consequently, English speakers and writers may not use the phrase very much anymore because a growing focus on safety has made that topic one that is associated with a positive connotation in the modern mind. Since the idiomatic phrase tends to express derision for excessive precautions, it may be less relevant today than it was in the past; of course, today’s elaborate safety systems may still inspire contempt in some individuals, who, in turn, might favor this term.