It looks like Weird Al may have joined SPOGG. So what does Grammar Girl have to say about less vs. fewer?
Less and fewer are easy to mix up. They mean the same thing—the opposite of more—but you use them in different circumstances (1). The basic rule is that you use less with mass nouns and fewer with count nouns.So, those signs over the express lane at Kroger's ought to read "15 items or fewer" rather than the popular but grammatically incorrect "15 items or less."
Count Nouns Versus Mass NounsNow I'm worried that I've scared you off, but it's easy to remember the difference between mass nouns and count nouns.
A count noun is just something you can count. I'm looking at my desk and I see books, pens, and M&M's. I can count all those things, so they are count nouns and the right word to use is fewer. I should eat fewer M&M's.
Mass nouns are just things that you can't count individually. Again, on my desk I see tape and clutter. These things can't be counted individually, so the right word to use is less. If I had less clutter, my desk would be cleaner. Another clue is that you don't make mass nouns plural: I would never say I have clutters on my desk or that I need more tapes to hold my book covers together.