Brian Kelly realized he had a knack for maximizing credit card rewards when he was working in HR at Morgan Stanley.
"My job was to go to around to all the college campuses and recruit the top computer scientists to join the bank," he tells CNBC Make It, "so I was traveling like crazy, racking up tons of points. … I was traveling around the world to places like the Seychelles for free and people were finally like, 'What trust fund are you on Brian?'
"There was no trust fund — it was just my points."
In 2010, he started a blog to share his best travel and points advice. What started as "just a fun little side gig," says Kelly, evolved into a lifestyle media brand that reaches millions of people across social media platforms and the Points Guy (TPG) website. Kelly quit his corporate job a year after his first blog post and sold the company to Bankrate in 2012, but he remained CEO.
Today, he remains the CEO of TPG and travels the world for next to nothing, thanks to the points he constantly racks up.
"I've got 25 credit cards and a near perfect credit score," Kelly tells Make It, "but that's because I really manage them. … A key thing with earning points through credit cards is you must pay your bill off in full every month. Otherwise, the interest that you pay will negate the value of those miles and points."
Of the 25 credit cards he has opened, there are three he says he can't live without:
Kelly uses the Amex Gold on a daily basis. It's a "no-brainer" for those who like to dine out or order in, he says.
Annual fee: $250
Sign-up bonus: Earn 35,000 points after spending $2,000 in the first three months. That's worth about $700, TPG estimates, noting: "It's not the most impressive, considering that we see 50,000- to 100,000-point bonuses on other cards regularly. But you may be able to get a 50,000-point welcome bonus through the Amex website, a referral link or through the CardMatch tool."
Point earning: Earn four Amex points per dollar spent on U.S. dining, four points per dollar spent at U.S. supermarkets (on up to $25,000 per year in purchases) and three points per dollar spent on airfare purchased directly from the airline.
"The 4X on U.S. restaurants is an especially strong earning rate," TPG notes, as is the point-earning potential for groceries: "Even with the cap, the Amex Gold becomes one of the very best cards for grocery spend."
Additional perks: $120 annual dining credit; $100 annual airline fee credit; no foreign transaction fees
This card "stands out for offering an application fee credit for Global Entry or TSA PreCheck — many other cards that offer this benefit have annual fees above $400," TPG reports. "Meanwhile, the Venture has a $95 annual fee that's waived the first year, and the Global Entry application fee credit is worth $100."
Annual fee: $95 (waived the first year)
Sign-up bonus: Earn 50,000 miles after spending $3,000 in the first three months. That's worth up to $700, according to TPG.
Point earning: Earn two miles for every dollar you spend on every transaction. Plus, earn 10 miles per dollar on hotels booked through Hotels.com. "That's an incredible return and one of the best, if not the best, bonuses on hotel spend on any credit card in the market today," TPG reports.
Additional perks: Application fee credit for Global Entry or TSA Pre-check (worth $100); extended warranty protection for everyday purchases; no foreign transaction fees
"For all other travel, like Uber and hotels, I'll put it on my Chase Sapphire Reserve for that three times Chase points," Kelly tells Make It. This card is a "complete no-brainer," he writes on his site, "especially for big spenders and frequent travelers."
Annual fee: $450
Sign-up bonus: Earn 50,000 bonus points after spending $4,000 in the first three months. That's worth $1,000, TPG reports.
Point earning: Earn three times points on travel and dining, and one point per dollar spent on all other purchases. Having triple points on travel and dining is a powerful combination, says Kelly.
Additional perks: $300 annual travel credit; Priority Pass lounge access; application fee credit for Global Entry or TSA Pre-check (worth $100); no foreign transaction fees
Don't miss: The best travel credit cards
Like this story? Subscribe to CNBC Make It on YouTube!