As the largest living generation, Millennials are a demographic every brand wants to charm. And while these people--roughly between the ages of 21 and 39--are certainly a diverse group, they do share some defining attributes.

1. They're the most tech-savvy generation ever.

They're a group 77 million strong which was the first to grow up with the Internet, cell phones and cable TV. In fact, according to Nielsen, Millennials rank their use of technology as the factor that most makes their generation unique.

2. Traditional ads don't work on Millennials.

They also don't respond to traditional advertising or marketing tactics, making it tricky to capture their loyalty as customers. Brands have to find creative ways to get their attention and keep it. According to a survey ( PDF) of more than 550 U.S. small and medium sized businesses conducted by Magisto, Millennial marketers understand how their peers think and are doing things much differently compared with older marketers. About 92 percent of Millennials at SMBs lead with social media in their marketing strategy, compared with the 79 percent of Baby Boomers who focus on word of mouth when it comes to marketing. Other findings:

  • Millennial marketers are 84 percent more likely to use social media than print ads.
  • Baby Boomers are 112 percent more likely to invest in radio ads, compared with Millennials.
  • One in three Baby Boomers invest in TV ads, compared with 0 percent of the Millennials surveyed.
  • Millennial marketers are 136 percent more likely than Baby Boomers to create videos for social media.

"There is an evolution happening around word of mouth marketing with video and social media at the center of the trend," the report reads. "For the younger generation, social media has surpassed word of mouth marketing and completely replaced TV advertising in one fell swoop."

3. Cash isn't king with Millennials.

They're also less likely to be walking around with actual money in their wallets. According to The 2017 American Express Digital Payments Survey:

  • 43 percent of Millennials say they rarely (35 percent) or never (8 percent) use cash for making purchases.
  • 28 percent report not currently carrying cash in their wallet, more than twice as many Boomers (11 percent).
  • 26 percent report not having used cash to make a purchase in over a week.

This kind of behavior is driving how merchants may do business in the future. About two thirds of the companies surveyed which offer cash or check payment options are seriously considering going cashless.

4. They see the financial benefits in having a mate.

According to a survey of hundreds of Millennials conducted by the digital banking app Varo Money, three-quarters of Millennials see a romantic relationship as financially beneficial, with the top perks being:

  • Living with a partner means cheaper rent (44 percent).
  • A mate helps figure out career strategy (37 percent).
  • Cooking for two saves money (26 percent).
  • Married people pay less in taxes (22 percent).
  • Going on fewer dates saves money (16 percent).

Plus, more than two-thirds--68 percent--of Millennials check their bank balances regularly and have a general idea of how much they can spend each month but don't formally categorize their spending or follow a strict budget. This casual approach doesn't mean they don't want to save. Rather, about half of those surveyed automatically save a portion of each paycheck. About 39 percent are keeping their eyes open for a higher paying job so they can save more. And 36 percent make coffee themselves instead of buying lattes.

5. They would rather invest in experiences instead of things.

Millennials are responsible for spending about $1.3 trillion a year, with $430 billion of that amount earmarked as "discretionary." But compared with older generations, people younger than 40 are less interested in buying cars and houses, and would rather collect memorable experiences rather than amass a bunch of stuff. That's according to a survey commissioned by Eventbrite and conducted by Ipsos, which found that 78 percent of Millennials would choose to spend their money on a desirable experience or event over purchasing a tangible item.

Fear of missing out (FOMO) might have something to do with it, considering that 69 percent of Millennials admit to experiencing it. "In a world where newsfeeds and social media broadcast what friends are experiencing, the fear of missing out propel millennials to show up, share and engage: a driving force behind the experience economy," the report reads.