Lisa Birnbach: “Anything old is preppier than anything new — that’s just a rule.”

Birnbach's new Preppy Handbook is due out in September

So, when it comes to fashion, go ahead and buy from new designers, but don’t forget to dig into your closet to revisit a classic pair of Top-Siders or your mom’s vintage Lilly shift, advises The Official Preppy Handbook author Lisa Birnbach, who recently announced a sequel to her famous guide to all things WASP.

Birnbach told the Los Angeles Times about a few additions that will appear in the updated book: “Vineyard Vines — they started in 1998 — and of course J. Crew — which wasn’t around then either. And we’ve got some Kenneth Cole [1982] and a little bit of Robert Graham.”

But, of course, some things never change: Lacoste, Sperry Top-Sider, Brooks Brothers and Ralph Lauren will still get plenty of play.