The need for Social Security reform has been well documented. The latest Trustees Report indicates the Social Security retirement trust fund will run out of cash by 2033 if Congress doesn't do anything. That could lead to some big changes in the near future.

But the Social Security rules change just a little bit almost every year. And even a little change can greatly impact the well-being of millions of senior citizens relying on their monthly benefits checks to make ends meet. 2024 is no different.

Here are three Social Security changes retirees need to know about in 2024.

A Social Security card sandwiched between $100 bills.

Image source: Getty Images.

1. The maximum Social Security benefit increased

A select group of Social Security beneficiaries will receive a monthly check of $4,873 this year. That's an increase from 2023's maximum benefit of $4,555 per month.

To receive that maximum benefit you must be 70 years old and have earned above the maximum taxable earnings level for at least 35 years in your career. That's something only a small portion of people will do.

Two things are going on to raise the maximum benefit.

The first is the annual cost-of-living adjustment. Every year the Social Security Administration adjusts retirees' benefits amounts by the average increase in inflation during the third quarter of the previous year. The 2024 COLA was 3.2%.

The second factor has to do with the way the SSA calculates your average wages to determine monthly benefits. It takes your 35 highest-earning years and adjusts them for inflation, using the average wage index, which tracks how much workers get paid on average each year. However, those inflation adjustments are pegged to the index in the year you turn 60. Any wages earned in your 60s or later aren't adjusted for inflation.

Younger retirees who consistently earned above the maximum taxable earnings have higher average monthly earnings because more of their wages are adjusted based on more recent wage data. That directly impacts how much their maximum benefit is. So, this year's group of 70-year-olds has a higher average wage than last year's group of 70-year-olds (who are now 71), and therefore a higher maximum benefit.

2. Retirees who claimed early can earn more without impacting their monthly benefit

If you continue to work while collecting early Social Security retirement benefits, you can earn more this year before the government withholds some of your benefits.

Beneficiaries younger than their full retirement age are subject to the retirement earnings test. Under the earnings test, the Social Security Administration will withhold $1 for every $2 you earn above the earnings threshold. There's a higher threshold for the year you reach full retirement age, and the SSA will only withhold $1 for every $3 earned above the threshold. Any wages or compensation from a job or self-employment count as earnings.

For 2024, the earnings test thresholds are $22,320 and $59,520. Those are up from $21,240 and $56,520 in 2023.

While the government will withhold some of your benefits if you earn above the threshold, it's not keeping it for itself. Instead, it uses the withheld amount to adjust your monthly benefit upon reaching full retirement age. For each month's worth of benefits withheld through the retirement earnings test, it adjusts your benefit as if you delayed applying for Social Security by one month.

Once you reach full retirement age, you're no longer subject to the earnings test, potentially letting your monthly benefit increase to its normal level once again.

3. The Social Security payroll tax covers more income

In 2024, workers will pay Social Security tax on their first $168,600 in wages. That's up 5.3% from $160,200 in 2023. That's notably higher than this year's COLA of 3.2%.

While this won't impact most retirees directly, the indirect impact is important. Social Security retirement benefits are increasingly funded by the taxes paid into the program as the SSA starts depleting the trust fund. As the taxable wage cap rises, the program should collect more tax revenue.

Importantly, only a small percentage of workers will earn above the wage cap. The SSA estimates just 6%. But the maximum taxable earnings number is tied to the average wage index, which reflects average wage growth. So, as long as average wage growth continues to outpace inflation, it should result in more tax revenue for the program, helping sustain current retirees' benefits.

Social Security still needs a major reform to help it last long term, but real wage growth is helping in the meantime.