I clean most of mine once each because I buy mostly used records. For new media I buy CDs. I included that bit about letting the stylus clean them because that's what the Rega manual says to do...seriously.

I don't clean records that I bought new, since I've taken good care of them and I don't clean records that don't appear to need it. I was given a collection of a few hundred 30- to 40-year-old records that were handled carefully and I haven't cleaned any of those. But I see around the web there are those who clean even a new record, presumably to remove mold-release agents?