Actually, I shouldn’t go anywhere near a store. Buying new clothes seems like the thing to do only when you’ve got nothing to wear. But, then again, maybe not. With the high-stakes fall-fashion season upon us, and with apparel sales rising, I conducted rack-side interviews around the city, heard woeful sagas of bad shopping habits and various personal theories about why so many keep repeating the same mistakes. But one thing seems clear: Friends shouldn’t let friends shop — they should stage interventions.

Listen to Cheryl Absi, 54, a dental hygienist from West Roxbury. She routinely buys clothing too small in hopes it will motivate her to lose weight: “I bought four dresses for my niece’s wedding,” she said, as if reporting on someone else’s behavior, “but I couldn’t fit into any of them.”

Hear Kristen Calvo, 23, an intern at Karmaloop, an online retailer in Boston. She’s a fashionista who’s unable to resist new trends. “I’ll want the style so much that I can’t stop until I get it,” she said. She recently bought three tops with of-the-moment cut-out shoulders. That’s a look recognized by fashion editors, but not Bostonians.

“A man on the T told me my clothing had a hole in it,” Calvo said. She also asked herself a question. “What was I thinking?”

It’s the same story in Weymouth, where Karen Donovan periodically buys bright colors to perk up her mainly black wardrobe, and then can’t bring herself to put on the pinks and blues she’s paid for, seemingly of her own free will. “This isn’t me,” she thinks even as she’s handing over her credit card.

Many of us confess to questionable shopping habits, but it doesn’t seem to be slowing us down much. US apparel sales hit $199 billion in 2011, up 4 percent from 2010, according to the NPD Group . Marshal Cohen, the market-research firm’s fashion-industry analyst, attributes the growth to “frugal fatigue” after a handful of years of recession.

The NPD Group doesn’t track the ups and downs of the unworn-apparel market. But the challenge posed by the seemingly simple act of purchasing clothing is so enormous that a clinical psychologist has written an entire 272-page book on the subject.

In “You Are What You Wear: What Your Clothes Reveal About You,” Jennifer Baumgartner argues that what seem like superficial wardrobe issues are actually manifestations of deeper life issues. “Over-shopping,” she explained, “can be a form of avoidance, from facing an immediate stressor or chronic emotional difficulty.

“Dressing the same you did in high school can be a way to hold onto the best time in your life when the here and now is not a happy place,” she added. “A disorganized wardrobe can indicate a life in chaos.”

That sounds pretty sad. But perhaps it’s a good thing. Recognition may be the first step toward persuading employers to offer the sartorial version of mental health days — “wardrobe days” — for those times when you just can’t stand to put on one thing you own.

Baumgartner, a clinical psychologist at EHP Behavioral Services, LLC, in Maryland, with a wardrobe consulting firm on the side, warns that once a shopper gets into a bad habit, purchase-wise, it’s hard to break free. “As with rote learning,” she said, “the repeated task no longer becomes something that requires any further mental energy. It’s practically an involuntary response.”

And who has time to think outside the box — or the black cardigan? Not a lot of working moms, Baumgartner said — or the president of the United States.

“I’m trying to pare down decisions,” Barack Obama told Vanity Fair in October, explaining why he keeps only blue and gray suits in his closet. “I don’t want to make decisions about what I’m eating or wearing. Because I have too many other decisions to make.”

I wonder if that’s really true, or if he was pandering to the crucial “nothing-to-wear moms” voting bloc? How do so many of us go so wrong so often?