I am currently working on a title for a fine art print show. I considered using the title "To Each Their Own" to highlight the different types of work. One member said that the title was grammatically incorrect.
Upon doing a bit of searching in the idiom realm, and found "each to his own" seems to be the appropriate use. But I have also found "to each their own" (the original title) used frequently, and would like keep it. This show will have a large attendance, so I would like to be able to say something if the grammar of the title is brought into dicussion.
"To Each his Own" would be grammatically correct. The problem with "To Each Their Own" is that "they/their" may be used as a neutral pronoun so it might not connect in people's minds with plural artists. And I am not quite sure how it indicates what you want to say.
However, if you really want it, then use it.