It's safe to say that nobody particularly enjoys saving for retirement, but if you want to be able to retire eventually, it's a necessary evil.

The problem with saving for retirement is that it's harder to save when the goal is so far in the future. When you know you can't even consider retiring for another 20 to 30 years, it feels like you have all the time in the world to save.

A broken white ceramic piggy bank atop a pile of coins

Image source: Getty Images.

However, the longer you wait, the harder it is to catch up. Say you want to have $750,000 saved by the time you turn 65, for example. If you start saving at age 25, you'd have to save around $300 per month (assuming you're earning a 7% annual rate of return on your investments). If you were to wait until age 40 to start saving, assuming you still earned a 7% return, you'd need to save around $950 per month to reach your $750,000 goal.

Sometimes it's tough to be able to tell whether you're on the right track to retire -- and then you find out quickly, when you're just a few years away from leaving your job and realize you barely have enough to last a couple of years in retirement. To avoid that scenario, there are a few red flags to look for that indicate you need to step up your saving game.

1. You're not contributing enough to your 401(k) to earn the full employer match

If you're fortunate enough to work for an employer that offers matching 401(k) contributions, don't let it go to waste. That's essentially free money, and by not taking advantage of it, you're leaving that money on the table.

For example, many employers will match 100% of your contributions up to around 3% of your salary. Say you're earning $50,000 per year, and you're contributing 2% of that -- or $1,000 per year. Your employer matches that, bringing your total yearly contributions to $2,000. Assuming you currently don't have anything saved and are earning a 7% rate of return on your investments, here's what your total savings would look like over time if you continued contributing 2% of your salary, versus bumping your savings rate up to 3% to earn the full employer match:

Years Total Savings When Contributing 2% of Your Salary Per Year Total Savings When Contributing 3% of Your Salary Per Year
10 $30,000 $44,400
20 $88,000 $131,600
30 $202,100 $303,200
40 $427,000 $640,800

Data source: Author's calculations.

So if you contributed just an additional 1% of your salary per year (amounting to another $500 on your end), with the employer match, it could make a $200,000 difference over a few decades.

Also, if you're not contributing enough to earn the full match, you're probably not saving enough anyway. While $427,000 may sound like a lot of money, it may not go as far as you think in retirement. The average person age 65 and over spends around $45,750 per year, according to the Bureau of Labor Statistics. And considering the average life expectancy is roughly 85 years, according to the Social Security Administration, that means if you spent 20 years in retirement and it cost $45,750 per year, retirement would cost a total of around $915,000.

In this example, if you want to have $915,000 saved by age 65 and you start saving at age 30, you'd need to save around $6,200 per year, assuming you earned an annual 7% return. If your employer is providing $1,500 per year in matching contributions, that means you'd be left with the remaining $4,700 per year -- or around 9.4% of your salary if you're earning $50,000 per year.

2. You don't know what percentage of your income you're saving

In a similar vein, if you have no idea what percentage of your income you're saving, it's tough to tell whether you should be contributing more.

For example, say you're currently saving $300 per month to your retirement fund, or $3,600 per year. That sounds like a lot of money, but if you're earning, say, $60,000 per year, it would be just 6% of your salary. If you invested at that rate for 30 years and earned a 7% annual return, you'd only have around $364,000.

Knowing how much you're saving in proportion to what you're earning also makes it easier to increase your retirement fund contributions when you get a raise or start a new job with a higher salary. If you were to simply continue saving $300 per month your entire life, you'd miss out on opportunities to save more when you start earning more. But if you consistently aimed to save, say, 10% of your salary, then when you received boosts in your income, you'd automatically be saving more.

Most experts recommend setting 10% to 15% of your wages aside for retirement. While that may seem like a lot, it's not so scary when you break it down bit by bit. For example, if you're earning $60,000 per year, 15% of that is $9,000. That breaks down to around $750 per month, or around $187 per week. Yes, that's still a lot of money. But if you invested $9,000 per year for, say, 30 years and earned an annual 7% return, you'd have over $900,000 stashed away.

3. You plan on relying heavily on Social Security benefits during retirement

According to the Social Security Administration, 21% of married couples and 44% of single beneficiaries rely on their benefits for at least 90% of their income. However, the average beneficiary only receives around $1,300 per month, or $15,600 per year.

This isn't to say you can't depend on Social Security at all. But because it's usually not enough to live on (or at least live on comfortably), you'll need to supplement that income with your own retirement savings.

To estimate how much you'll receive in benefits, you can use the Social Security Administration's online calculator. This will give you an idea of what to expect, which will help you determine how much of your own money you'll need to save to cover all your expenses in retirement.

Saving for retirement isn't fun, and it's easy to put it off for another day. But it's important to check your progress regularly to make sure you're on the right track, which will make your life much easier when it finally is time to retire.