In your 20s, as you start your career and make real money for the first time, your spending changes. After living with your parents or in a college dorm, you can afford a place of your own and might want to splurge on the spot with the amazing rooftop deck. You might have some disposable income for the first time -- even after making the monthly payments on those student loans -- and want to take a weekend trip each month with friends.

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Before signing that apartment lease or booking a hotel for that getaway, don't forget to add one monthly "bill" into your budget: a contribution to your retirement account. The best time to start saving for retirement is when you start earning.

How much you should save depends on the type of life you want to lead later. Do you envision yourself as a world traveler when you retire or a homebody? Setting goals and milestones to reach at ages 30, 40, 50 and 60 will help you have money to live when you no longer bring in that weekly paycheck.

There isn't one recipe for success when it comes to retirement planning. Each plan is unique, depends on your lifestyle and is best designed with the assistance of a financial planner. Still, some general guidelines do exist, and here they are.

Age 30: The 1X Recommendation

By age 30, you should have saved an amount equal to your annual salary for retirement, as both Fidelity and Ally Bank recommend. If your salary is $75,000, you should have $75,000 put away. How do you do that?

"When starting your career, commit to automatic savings of 20% per year into your 401(k). It will discipline you to live and give on the remaining 80%," said Jason Parker of Parker Financial in the Seattle area, author of "Sound Retirement Planning" and host of the "Sound Retirement Radio" podcast.

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Age 30: Planning Starts in Your 20s

Many Americans don't sign up for a 401(k) in their 20s, meaning they aren't taking advantage of a potential employer match.