One of the biggest obstacles to saving for retirement is often that little voice that tells you your nest egg will have to wait.

You're probably thinking a few dollars here and there aren’t going to make a big difference, so your retirement fund can wait until you can start contributing at least a few hundred a month to a 401(k) or IRA. Right?

If you find yourself using this logic, so do a lot of people: According to a 2016 GoBankingRates survey, a third of Americans have exactly $0 saved for retirement. But the sooner you start investing in a retirement account, the sooner that money has an opportunity to grow — and even a little bit has the potential to go a long way over time.

Read on for some pain-free strategies that could help you free up some cash — because every bit you can save and invest for your future is money well spent.

1. Skip One $20 Purchase a Week

Jeff Rose, CFP®, founder of personal finance site Good Financial Cents, says that putting $80 into a pre-tax retirement account, like a Traditional IRA or 401(k), translates to a nearly $1,000 tax write-off, as the contributions help reduce your taxable income. “That is a short-term benefit, but the real benefit is the sooner anyone starts contributing to their retirement accounts, the sooner that money starts gaining interest and begins the compounding process,” he adds.

For example, if you put $80 a month into a retirement account with hypothetical growth of 7% a year, and did that for 30 years, you’d have more than $90,000 at retirement. By contrast, if you waited and made contributions for 15 years, you’d have less than $25,000 waiting for you. See the difference starting early can make?

2. Slash a Big Monthly Spending Category by 10%

Find a budget category that could use a trim and try to cut just 10% from it. Maybe that means skipping a few work lunches a month, or not going to the movies as much.

If you categorize your expenses into fixed costs and flex spending, you could try cutting a variety of things to help you reach that 10%. Perhaps a subscription or two you rarely use can be eliminated to lower your total fixed number, while a combo of one less shopping excursion and one fewer trip to the gas station a month can bring your flex spending down.

By starting small, you’re minimizing the chances of feeling deprived. “Our brains are wired to avoid pain. The larger the change from ‘normal’, the greater the pain,” says Michael F. Kay, CFP®, author of "The Feel Rich Project: Reinventing Your Understanding of True Wealth to Find True Happiness."

Kay likens the concept to making small changes to your diet or exercise. “If you decide to make big changes and eat nothing but celery and carrot sticks, your brain will rebel because it feels denied,” he says. “It's not long before you're swimming in brownies. By making small steps with achievable goals, each success builds strength and resilience.”

3. Try a Financial ‘Fast’ Once a Quarter

Elon Musk once famously shared a story about successfully living off a grocery budget of $30 per month as a way to test how little he could survive on.

Of course, we’re not advocating you go to that extreme. But if you’re the type who likes to challenge yourself, consider taking a week once every three months or so to live as frugally as possible; then transfer what you saved over a typical week into your retirement account.

Of course, if taking a financial fast just leads to binge-spending afterward, then you know this strategy isn’t for you.

4. Make Cash King for a Week

For those of you who use your credit card for a pack of gum, try going cold turkey on your plastic for even if just a week and see if you end up spending less. If you do, consider doing this weekly.

A 2016 study published in the Journal of Consumer Research found that when people pay by cash for an item versus a credit, debit or gift card, they place more emotional weight on that purchase, thus making it feel more painful to part with that money.

Plus, by cutting back on charging, you’re helping keep your credit card debt in check. “Any [credit card balance] that you do not pay off in full each month is going to cost you money,” says Rose, either in the form of interest, or by potentially lowering your credit score, which will affect the interest rates you’ll pay on other types of borrowing.

5. Redirect Old Debt Payments

If you’ve recently finished paying off a car, a credit card, a student loan or a personal loan, think about diverting that old payment into your retirement account.

Scientifically speaking, with this strategy, you’re using the psychology of “framing” and “mindlessness” to your advantage.

Because your brain hasn’t become attached to the extra money yet, you can trick yourself into thinking that you don’t actually have additional income at the ready. Rather, you’re just continuing to pay a “bill," except now it goes to someone else (in this case, your future self).

Certified Financial Planner Board of Standards Inc. owns the certification marks CFP®, CERTIFIED FINANCIAL PLANNER™, CFP® (with plaque design) and CFP® (with flame design) in the U.S., which it awards to individuals who successfully complete CFP Board's initial and ongoing certification requirements.