As my last post discussed “amount” vs. “number,” a closely related topic are the two words in the subject line: “less” and “fewer.”
Just as “amount” is used for objects you can’t count, such as traffic, milk, luggage and equipment, “less” is the adjective you need for those uncountable nouns:
You carry less luggage than you used to when you fly. You need less kitchen equipment than your brother does. We definitely do not experience less traffic than we did five years ago.
“Fewer” is used for countable nouns, such as suitcases, roasting pans, glasses of milk, and automobiles:
If you want fewer cars on the road, move to Montana. Children today drink fewer glasses of milk than I did when I was younger. I could manage with fewer pots and pans than I currently own. I have fewer pieces of luggage than I did 10 years ago.
(Notice that in the last sentence, the subject is “pieces,” not “luggage.”)
My last post contained fewer words than this one.