The whole “don’t end sentences with a preposition” rule is not a real rule in English at all. Some pompous asshats like John Dryden claimed it should be a rule in the 17th century because that’s a rule in Latin, and then everyone just repeated the “rule” forever. But notice how English is not Latin and has entirely different grammatical rules? Weird huh? And notice how a phrase like, “That’s a policy I can agree with,” sounds way more natural and easily understood than, “That’s a policy with which I can agree.” Both are technically correct, but the former is generally preferred and much more common phrasing among native speakers despite the supposed rule against it. It’s up there with “i before e except after c”, “never use double negatives”, and “don’t split infinitives” for English rules that everyone has been told that aren’t actually rules at all and that we all break on the reg.
According to the Merriam-Webster’s Dictionary of English Usage this rule was first introduced in a rather tentative form in 1770, when the grammarian Robert Baker stated that less ‘is most commonly used as speaking of a Number; where I should think Fewer would be better’.
The whole “don’t end sentences with a preposition” rule is not a real rule in English at all. Some pompous asshats like John Dryden claimed it should be a rule in the 17th century because that’s a rule in Latin, and then everyone just repeated the “rule” forever. But notice how English is not Latin and has entirely different grammatical rules? Weird huh? And notice how a phrase like, “That’s a policy I can agree with,” sounds way more natural and easily understood than, “That’s a policy with which I can agree.” Both are technically correct, but the former is generally preferred and much more common phrasing among native speakers despite the supposed rule against it. It’s up there with “i before e except after c”, “never use double negatives”, and “don’t split infinitives” for English rules that everyone has been told that aren’t actually rules at all and that we all break on the reg.
Same with less vs. fewer: