“Most of the world is not with me, but I don’t care,” Iris Apfel says toward the close of the late Albert Maysles’ documentary about the ninety-year old style maven. Ironically—or if you’re of a more cynical bent, out of clever calculation—it’s an attitude that has made her, in her own words again, a “geriatric starlet” for her idiosyncratic taste in fashion. In the eponymous film, his penultimate one, Maysles celebrates her vitality in sharing the fruits of a lifetime’s collecting.

It’s her attire, of course, that one first notices about Apfel, who’s on screen virtually nonstop here. She dismisses staid, conventional ideas about how one should dress, and aims instead to put together items she’s acquired from all sorts of places, from the highest-end stores to thrift shops, to create outfits that look like no one else’s and inevitably catch the eye. Then she adorns herself with scarves, bracelets, necklaces and her trademark “big eyes” glasses as accessories. It’s her refusal to conform to the expected canons of fashion that have made her a celebrity, a woman whose closets have provided the stuff for numerous museum exhibits, including the Metropolitan Museum of Art (where “Rara avis: Selections from the Iris Apfel Collection,” was a huge hit in 2005, leading to its move to other venues). And no less than the Peabody Essex Museum in Salem, Massachusetts, will act as repository for a considerable portion of her couture collection; at the end of the film she’s shown selecting the items that will trickle there over time.

But “Iris” isn’t merely concerned with clothes: it’s also a paean to marital longevity. Iris has been married to Carl Apfel for more than 66 years (the celebration of his hundredth birthday is covered in the film), and the couple’s scenes together are warm and funny. We’re also told about the company—Old World Weavers—that they founded in 1950 and ran together until 1992. The firm specialized in offering authentic fabrics from times past, which were often used in restoration projects (including some at the White House) as well as in the homes of the rich and famous.

The business must have been profitable, since the Apfels travelled widely and Iris bought whatever caught her fancy on their trips—and not just clothing. (When asked about children, Iris replies bluntly that they made the decision not to have any, because—as she puts it—a person can’t do everything.) Home movies show their sprees, and we’re treated to visits to their apartments in New York and Palm Beach, which are filled with stuffed animals, toys, statues, even electric trains—in short, knickknacks and oddities of every sort. Storage units accommodate a host of overflow items. The overall impression is of a miniature version of Kane’s Xanadu.

But what’s gained Apfel her fame are the clothes, which have gained her recognition as an icon of individuality. Maysles follows her as she offers courses to students from the University of Texas, goes on shopping expeditions with admirers (sometimes in a wheelchair, sometimes with a cane), gives advice to women about choosing ensembles that defy convention but suit their personalities, and confers with employees and Bergdorf Goodman about a window display featuring items from her collection. It’s obvious that she enjoys the attention and the activity; in an interview her nephew says that he sometimes advises her to slow down, but the words have little effect. Still, age is obviously a concern: when asked what keeps her awake at night, Apfel will merely say “matters of health,” and when she falls and needs hip surgery, she keeps the severity of the injury from Carl to avoid upsetting him.

The documentary leaves little doubt that Maysles was captivated by Iris Apfel, and it’s probable that you will be too, even if you aren’t persuaded to follow her fashion lead. “Iris,” moreover, serves as a tribute not only to her, but to the director as a testimony to both his body of work and to his own virtuosity in old age.