Where Did That Preposition Get To?
I think it was Winston Churchill who said, in response to a misguided editor’s rearranging his words so that a sentence would not end with a preposition, “This is the sort of English up with which I will not put.” [Sometimes quoted as “arrant nonsense…,” which I think is eminently better.] The point is that the “rule” about not ending a sentence with a preposition is not a rule at all; it’s a superstition.
While it is not undesirable to avoid ending with a preposition, there are many idioms or sentence constructions which lose their impact when rearranged. There are, of course, instances where an ending preposition is blatantly wrong, usually because the preposition is unnecessary or redundant.
For example, asking “Where’s the dog at?” is wrong because at, in this case, is redundant. At specifies placement, as does the pronoun where.
To say, “I need something to put this garbage in” is not wrong. It’s a shorter, informal version of the statement “I need something in which to put this garbage.” Similarly, asking “What school is your child in?” is not wrong, as it is actually simple inversion of the words “In what school is your child?” Both versions are correct; the difference is that the first is informal, and the second is formal. And perhaps that is where this superstition arose. Most of our teachers were interested in teaching us to write formal essays and theses. In those venues, you would rarely be correct in using the informal pattern.
So stop panicking. If you’re writing informally, or talking to someone, be natural and informal. Get nitpicky about the formal, “correct” versions only when you are presenting a thesis or some other scholarly pursuit.