There's a vast and complicated industry around planning for life in retirement, but if you're thinking about how you can call it quits earlier or live more luxuriously when you do retire, the calculus can be remarkably simple.

"The big knob you can turn is cost of living," says Tommy Sikes, a certified financial planner and founder of Traveltirement, where he highlights affordable homes in France and Italy through a newsletter and social media channels.

"It might cost you $70,000 a year to have a middle-class retirement in the United States," Sikes says. "If you have that money in southern Italy, you can live like a king, including renting or purchasing a property."

If you're hoping to retire in style while keeping costs low, a European retirement may be right for you. But as you begin searching for chateaus, keep these three tips in mind.

1. Think outside of popular spots

If you were looking for an exciting but cost-effective retirement destination in the U.S., you'd likely scratch New York and Los Angeles off your list right off the bat. The same goes in Europe, says Sikes.

"Paris, Rome and Milan are still going to be expensive," he says. That's true for luxury vacation hotspots such as Lake Como and Saint-Tropez, though you may not find what you're looking for in those places anyway.

"The heart of these countries is when you get further into the countryside," Sikes says. "We're not talking about living in the middle of nowhere. There are hundreds, if not thousands, of small towns and villages that still have infrastructure. They still have high-speed internet and medical offices. It's just that people may not see them as glitzy or glamorous," he adds.

Nevertheless, life can feel glamorous if you can spend less on basic living expenses and more on doing the things that make you happy.

"A couple I know lives in southern Italy in a coastal town. So they have beaches, a walkable town, restaurants, bars, trains — they live on the main line," Sikes says. "He tells me he lives on $1,500 a month."

2. Know the residency rules

Before you start your search, you'll have to figure out what the rules are when it comes to owning or leasing property and generally residing in the country you plan to retire to.

Part of the reasoning behind Sikes' focus on France and Italy is that the countries' rules are favorable to Americans looking to buy property there.

"There are zero restrictions on Americans buying property in Italy or France," Sikes tells CNBC Make It. "You don't have to be a citizen. You don't even have to be a resident. You can literally buy something remotely."

Once you sort out whether you're able to buy or rent in another country, residing is another question. For many would-be continental retirees, a half-and-half solution is a good first step. Valid U.S. passport holders can reside anywhere in the Schengen area, which includes all of the European Union except Ireland and Cyprus, for up to 90 days during any 180-day period.

"You could go from January to March, then leave for 90 days, then go back for July, August, September," Sikes says.

For full-time residency, you'll have to explore whether citizenship or visa rules make sense for your retirement plan.

3. Work with professionals

Living on a fixed income in retirement always requires a good deal of planning, and doing so abroad adds another layer of complexity.

You may have a pretty good handle on how distributions from your 401(k) and Roth IRA are handled from a U.S. tax perspective, but that picture could look drastically different in another country depending on international tax treaties.

Even Sikes, a CFP, knows that it's important to have people on both sides of the ocean that can help you plan. "You need people in the country — boots on the ground to help you through the administrative stuff," he says. "Some of these countries are famous for their bureaucracies."

If you're planning on using a property part time, and plan to rent it when you're not there, you'll need to establish a relationship with a property manager that you trust. Even if you're not renting it out, you'll have to plan for what happens when you're not there for three months.

Even before you cross that bridge, if you're making real estate deals, there's a good chance the selling agent won't speak English and the documents will be in the native language. Those are just a couple more reasons why Sikes strongly advocates enlisting help.

"There are many reasons to budget for working with a professional and not trying to figure it out for yourself."

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