The words ‘one’ and ‘none’ often cause grammatical chaos. Geoff from Seattle writes:

I wonder how to phrase this: ‘by doing this chore before you go to bed you will have one fewer things to worry about in the morning’. I can think of three ways to do ‘one fewer things’:

  1. “one fewer things”
  2. “one fewer thing”
  3. “one less thing”

I like ‘fewer’ over ‘less’ because it is a discrete count. But is it ‘things’ or ‘thing’? Thing matches in count to the ‘one thing’ you are doing. Actually, ‘one less thing’ sounds most natural, even though ‘less’ is commonly not used with discrete counted items, in this case ‘things’. What do you think?

Well Geoff, I think you’ve missed out the best answer, which is ‘one thing fewer’. ‘Less’ is incorrect; your discrete count argument is sound. However, ‘thing’ must be singular, as the object of the clause (the ‘one fewer thing’) is singular. I would change the order of your second suggestion, for no other reason than it sounds better.

Update: I stand corrected – as explained in John’s comment below, ‘one less thing’ is correct.
I would probably take a different approach and change the sentence structure; but I’ll leave it to GrammarBlog readers to suggest alternatives.