Which writers should the writers be reading?

A few days ago I read an interview with a new fantasy writer, in which
he said that he didn't feel very well read in the genre. This raises
the question: how much SF/fantasy should an author have read before
they start writing their own stuff, and by which authors?
And how different is the reading list for established authors?

I'm not naming the author in question, to try to stop this topic being
about him in particular rather than new authors in general.  Having
said that, when he was a teenager he was a big fan of Moorcock and
LOTR, and as an adult he's read a lot of literary fiction and crime
fiction. And he thought A GAME OF THRONES was great.