The kids I tutor attend schools with $50k tuition and summer in the Hamptons. Their parents still often forget to pay me on time.

• When I taught and tutored kids of wealthy NYC families, I wore cheaper clothing than the students.
• It's hard to get parents to pay invoices; I called one mother every day for two weeks to get a check.
• This is an adapted excerpt from "I Left My Homework in the Hamptons" by Blythe Grossberg.

Hardly a tutoring session goes by when a high school student I tutor, Lily, does not receive a package with high-priced clothing. Her housekeeper, Ruby, a no-nonsense woman from Barbados who is studying for her college degree, is kept busy toting in packages from J. Crew and Splendid that seem to make Lily momentarily very happy in between writing papers and studying for math tests with her corps of tutors in nearly every subject.

Lily is a slightly plump girl with blond hair, pale skin, and blue eyes. Her mother is petite and thin, and she says out loud that she hopes "squash will allow Lily to lose her baby fat." Her mother keeps a precise calendar so that her daughter's tutoring appointments are neatly staggered.

In the midst of tutoring sessions, Lily rips open boxes with abandon to reveal outfits that seem far too tropical to wear in February in New York City. They also seem far too daring to wear to school — such as the leopard-print jumpsuit whose arm holes plummet well past her pink bra.

The students I tutor wear nicer clothing than I do

She gets her own budget and picks out her own clothing. She favors Comme des Garçons, and I briefly fall in love with the high-top canvas sneakers and mariners' shirts with hearts on them until I discover that the shoes cost upward of $135 (many cost several hundreds of dollars) and a simple cotton T-shirt costs more than $150. That means that one hour of tutoring would not pay for that shirt plus taxes.

I quickly get used to having cheaper clothing than most of the kids I teach and tutor. One unkind seventh-grade girl whose clothes are far nicer than mine asks me, "Where did you get that vest?" It was a vest I think I had bought in one of those secondhand stores, definitely not the chic kind where Prince bought his raspberry beret, and though I'm not proud to admit it, I never wore it again.

Clothes are often a bargaining chip for Lily. By age 16, she already has a signature style, and clothes are used as a reward. An only child, she often isn't happy with her parents' constant business trips, and they allow Lily to raid her mother's closet to keep her from complaining too much.

Her parents return home from Paris or Tokyo with expensive clothes. Days off with her mom, a busy executive, are often spent shopping, as that's how her mom relaxes. Lily and her mom head to Madison Avenue and then stop for a gelato or pastry at Sant Ambroeus, the New York branch of a Milanese pasticceria (there's also a summer branch in Southampton on Long Island).

Tutoring means more to me than having credentials — it's a way to survive

Lily's mom, Lisa, only shares my name with her besties, the women she sweats in Pilates with, and I am flattered that the moms think I'm a kind of tutoring messiah. Other than my grandmother, no one has ever endowed me with that kind of power before.

Of course, there is the Fifth Avenue mother who almost doesn't hire me when I ask her, "Which side of Fifth Avenue do you live on?" She pauses for a menacingly long time and replies acidly, "There is only one side." I hadn't recalled that one side of Fifth Avenue is the entry to Central Park in the prime residential areas uptown. I lacerate myself about that out-of-towner mistake for the better part of a month, but I still get the gig.

Getting tutoring gigs is more than just a lark to me. It is not just about my credentials or the reality that I can speak about most novels and eras of history with my eyes shut. I'll remember the year of the reunification of Germany long after I am hauled off to assisted living. That's just the way my mind works. But for me, tutoring means the difference between being able to pay for my son's babysitter or not. It means finally being able to cross my legs without showing the holes in my shoes.

I struggle to get wealthy parents to pay me on time

Because so many private-school kids must endure college-level classes taught by PhDs who don't believe in offering extra help, the tutoring industry in Manhattan and parts of Brooklyn is incredibly robust. The pay is what the market demands. There are tutors who charge several hundreds of dollars per hour. SAT and ACT tutors are in their own league. Several companies jumped into this Wild West years ago with prices that start at $300 and go up to $800 — per hour. For this price, they had better come up with results.

I charge $125 to $175 per hour (though I have a sliding scale for families with need, and I've volunteered my time to tutor for organizations that help underprivileged kids get private school or equivalent educations), and I never go up on my rates, though many people tell me I should.

No matter the rate, sometimes it's hard to get families to pay their invoices, even people who have Hamptons houses (the Hamptons comprise the dazzlingly expensive resort area at the end of Long Island where I couldn't afford to eat lunch, much less to stay) and send their kids to $50,000-a-year private schools without any financial aid. Even if they agree to pay this amount, they don't actually pay when the bill comes. Most do, but there are always one or two holdouts.

The parents sometimes seem oblivious that we're in a different income bracket

There was one mother who didn't pay me for months. Meanwhile, I saw pictures of her in glossy magazines appearing at society events. My accountant told me to write off my bill, but the Taurean-stubborn streak in me made me call this überrich mother every day for two weeks until the check for $600 — then a great deal of money to me — showed up in my mailbox, written from her private wealth-management account. Other parents take a long time to pay because accountants handle every payment they make, and they actually can't write any checks — or so they say.

Other parents never mention money. When I speak to them about my services, they don't even ask my fee. It's astounding. I feel worried, not knowing when or how I should bring it up, so I usually send them a follow-up email telling them what it is. It is amazing that money isn't something they talk about. They seem oblivious to it, just as when they ask me whether I'll be in the Hamptons over the summer. This type of question shows no awareness of what average people earn and what things cost. Some of the parents have inherited money, but some work for it. Surely they must realize their children's teachers earn well under $100,000, unless they have been teaching for a very long time.

Though this sounds like a lot on a national scale, in New York City it does not cover much. It barely pays the rent on a basic two-bedroom apartment and the cost of living, unless one is fortunate enough to have bought an apartment years before the gentrification of many New York neighborhoods.

One mother, looking at my black boots, asks me, "Prada?"

"Banana Republic," I reply, wondering how she could think that I could afford $800 pairs of shoes. The Banana Republic I went to was at an outlet mall in Massachusetts where shoes cost less than a taxi ride from Brooklyn to Manhattan.

Excerpted from "I Left My Homework in the Hamptons: What I Learned Teaching the Children of the One Percent" (Hanover Square Press, August 17, 2021). Reprinted with permission from Hanover Square Press.