Social Security's rules can be more complicated than you think. Unfortunately, the challenges in understanding the inner workings of the retirement benefits program can lead you to make errors without even realizing it. This can cost you some of the financial security you deserve as a retiree.

To make sure you don't inadvertently make an expensive mistake, here are three common errors you may not even know you're making -- along with some tips on how to avoid each one. 

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1. Failing to calculate your break-even age

One of the biggest mistakes people make -- and don't realize they're making -- is not knowing their break-even age before they decide when to claim benefits.

You can start collecting Social Security any time between the ages of 62 and 70. Each month you delay the start of your retirement benefits, the amount you receive increases -- but you pass up an entire monthly check.

To decide the best age to start your payments, you'll want to calculate your break-even age based on the time frames you're considering for claiming benefits. To calculate your break-even age:

  • Determine how much your monthly Social Security check would be at different ages you're considering for claiming benefits. You can do this by signing in to mySocialSecurity.gov
  • Calculate the difference between the earlier and later claiming age. For example, let's say you're deciding between claiming a $1,600 standard benefit at a full retirement age of 67 or a reduced benefit of $1,120 at 62. The difference in monthly benefits is $480 per month. 
  • Figure out how much income you'd pass up if you waited until the later age. In this example, you'd give up five years of an $1,120 monthly benefit -- $67,200 for the five years.
  • Determine how long it would take for your higher future benefit to make up for the missed income. It would take you 140 months for the extra $480 due to the delayed benefit to make up for the $67,200 you'd miss as a result of waiting until 67 to claim benefits instead of starting them at 62. 

If you think you will live at least another 140 months after turning 67, delaying your benefits claim would make sense.

You should always calculate your break-even point for any claiming ages you're considering because otherwise, you're not being as strategic as you can be about maximizing lifetime benefits. 

2. Working too few years to maximize your benefit

Another mistake many people make is not working long enough to maximize their benefit. Your benefit is calculated based on the inflation-adjusted wages from your 35 highest-earning years. 

If you work less than 35 years, your benefit will be lower because the calculation will include years of $0 wages. If you work exactly 35 years, every single year you worked will be factored into the calculation -- including those years when you may not have made much since your career was just taking off or if you were unemployed for part of the year.

If you are earning more money toward the end of your career than at any point before, you can maximize your benefit by working an extra year or two at your higher salary and replace lower-earning years in your benefits calculation.

3. Not coordinating with your spouse to decide on a claiming strategy 

Finally, married couples need to work together to determine a strategy to get the most combined Social Security income -- and to make sure the surviving spouse is protected financially. 

Usually, if there's an earning disparity, it makes sense for the lower earner to claim their benefits first so the higher earner can delay and increase their bigger benefit over time. This can also maximize survivor benefits too, since the person left behind gets to keep the larger of the two Social Security checks after their partner passes.

By avoiding these mistakes, you can get the most out of Social Security and, in turn, your retirement. The additional income may not be life-changing, but every dollar can make a difference once the paychecks have stopped coming in.