Most people often use the words ‘fewer’ and ‘less’ as though they meant the same thing, but they don’t. ‘Fewer’ refers to amounts that can be counted individually. In other words, a specific number of items is known or knowable. ‘Less’ refers to a general amount that is not quantifiable. The number of items cannot be counted or measured. Here are some examples:
‘I have fewer tenants now than I did ten years ago.’ I know how many tenants I had 10 years ago and how many I have now.
‘One bedroom apartments cost less than two bedroom apartments.’ While this is true, it is a generality.
There is a sign over the express lane at the Safeway store in in Orinda that says ’12 items or less’, but that is bad grammar. It should say ’12 items or fewer.’ You can count the number of items in your shopping cart. Supermarkets always seem to get this wrong. There used to be a TV show set in a supermarket titled ’10 Items Or Less.’ It was not a very good show.
(My thanks to Matt Todd, an SAT tutor, for telling me about this.)