when to use the word "fewer" instead of the word "less"
They actually mean different things. "Fewer" applies only to number (counting things) but "less" applies more generally to reductions or comparisons of many alternative kinds. Consequently it is (should be) clear that "less" is the more general and "fewer" the more specific and narrowly applicable term. Consequently using "fewer" outside the numerical context is simply incorrect.
In a similar vein, "impact" is now almost universally used in public rhetoric to indicate any effect of anything on anything else. I got so pissed off by this recently that I spent half an hour with a thesaurus, in which time I identified over 60 specific verbs that have been generally supplanted by "to impact" or "to have an impact on". Each of these specific verbs conveys more information in its appropriate context about the nature (and even in some cases the consequences) of the effect than the general term "impact."
If regret for loss of clarity and precision in communication is pedantry, long live pedantry.
Biting the hand that feeds IT
