Fewer vs. Less
Q. The store where I shop has two signs next to each other at the checkout counter: "12 items or less" and "12 items or fewer." What's going on?
A. Sounds like an insecure manager to me. The general rule for the difference between less and few/fewer is this: (1) Use few/fewer to describe things that can be counted—
fewer cigarettes, fewer cars, fewer jobs. (2) Use less to describe things that cannot be counted—less smoking, less traffic, less employment. So “12 items or fewer” is correct.
However, to be fair, in idiomatic English—and more and more in formal usage—less is being used with a plural noun denoting time, amount, or distance: There are less than two minutes to play in the game; She makes less than $40,000 a year; We have less than three miles to go. In other words, sometimes separate, countable elements (which would therefore need the word fewer) are treated as an unbroken unit and the word less is then acceptable. Until the dust settles, play it safe and follow the rules in paragraph one.