Why buy that dress, movie, car or bike when you can rent?

A power tie for a job interview, an educational puzzle for a teething 2-year-old, a dress for a White House gala. A decade ago, we bought these items at the mall. Today, we rent them with a smartphone.

Pay a monthly fee. Rent your object of desire. Return it when it bores or becomes useless. It’s easy, on-demand, noncommittal. Consumerism is being redefined for the mobile age, and the model is spreading among professionals and families in ways that were little anticipated, even by the venture capitalists funding this new era of cooperative capitalism.

Businesses such as Netflix, Zipcar and Capital Bikeshare have fueled this culture of borrowers and lenders. Experts have coined a term for the phenomenon: collaborative consumption. The sharing economy. It’s moving past Generation Y to reach a broader audience, just as a host of companies pave the way for the sharing of niche products.

“I’ve been renting the tartan plaid ties that are trendy right now,” said Masai McDougall, 29, a lawyer at the D.C. office of Bingham McCutchen. “It’s nice to try out styles without having to spend 100 bucks on a tie.” That’s the sensibility that drove native Washingtonians Zac Gittens, 28, and Otis Collins, 27, to create Tie Society in November.

The childhood friends run their business out of Gittens’s rowhouse in Adams Morgan. For a monthly minimum of $11, they mail members the sorts of designer ties found only in high-end department stores. Clients select organically sanitized ties from 300 styles. When a subscriber tires of the ties or wants to try a different style, he mails them back and selects more.

The start-up went from local to national in less than a month. Quaite Dodson, 21, a college student and Bank of America teller from Sierra Vista, Ariz., needed ties to wear to work, and he found the Netflix-style rental model perfect for an entry-level salary. “I found it on Reddit and joined. . . . I’m not a corporate big fish yet, and you need to dress for the position you want, so Tie Society gave me a better selection of designer ties than what I normally get at Macy’s,” Dodson said.

It was convenience — not cost — that drew Juliet Teimoori to rent educational toys online. “The biggest draw for me was that it helped get rid of the clutter,” said Teimoori, 31, an account executive from Albany, N.Y., who recently signed up for a subscription to the two-month-old Spark Box for daughter Della, 3.

For $23 a month, the company delivers a box of educational, creative and, yes, sanitized toys to your doorstep. The roller-ball shape sorters or “Mozart Magic Cubes” are tailored to a child’s learning style. When little Suzy has mastered them, ship them back and get a new assortment.

It’s a concept that Teimoori is buying into — or at least renting.

“These companies couldn’t have existed five or 10 years ago . . . without the ubiquity of an increasingly mobile Internet,” said former AOL chairman Steve Case, founder of Revolution, a Washington-based investment firm that has stakes in Zipcar and LivingSocial.