I can guarantee with near 100% certainty that unless you deal with people who speak in a formal style as their normal vernacular, you do not hear it either commonly nor consistently used in a correct manner.
- the OED remarks "whom is 'no longer current in natural colloquial speech'" and notes multiple cases in Shakespeare, Defoe, Chaucer and the King James Bible where "whom" is used "incorrectly" by modern standards
- Howard Lasnik and Nicholas Sobin describe whom as "It is commonly assumed that the English interrogative/relative pronoun whom is parallel to him and them in manifesting objective pronominal Case...Whom in modern English derives from a set of extra-grammatical rules...[used to generate] products that have a 'prestige' status. Whom differs markedly from intuitions about the use of personal pronouns. http://ling.umd.edu/~lasnik/ and the presentation http://academics.utep.edu/Portals/878/papers/whom_paper_vanc...
- Edward Sapir dedicated significant studies to the obsoletion of whom. In "Language: Intro to Study Speech" he remarks: "It is safe to prophesy that within a couple of hundred years from to-day not even the most learned jurist will be saying "Whom did you see!" By that time the 'whom' will be as delightfully archaic as the Elizabethan 'his' for 'its.' No logical or historical argument will avail to save this hapless 'whom'"
- Thurber provided this example: "A common rule for determining whether 'who' or 'whom' is right is to substitute 'she' for 'who', and 'her' for 'whom', and see which sounds better. Take the sentence, 'He met a woman who they said was an actress'. Now if 'who' is correct then 'she' can be used in its place...'He met a woman she they said was an actress'.
- Chomsky wrote that similar non-grammatical structures that only exist in grammar books are: "...a violation of natural law. In fact, a good deal of what's taught is taught because it's wrong. You don't have to teach people their native language because it grows in their minds, but if you want people to say, "He and I were here" and not "Him and me were here," then you have to teach them because it's probably wrong.
- Mair notes that: "whom is moribund as an element of the core grammar of English, but is very much alive as a style marker whose correct use is acquired in the educational system [, where it is taught]. [The use of whom] is highly restricted, but rather than disappear entirely, the form is likely to remain in use for some time to come because of its over prestige in writing."