Warren Buffett's 6 golden rules for investors after retirement

Warren Buffett's retirement advice focuses on low-cost index investing, paying off high-interest debt, maintaining cash reserves, staying within one's circle of competence and living frugally. His long-standing principles offer lessons on building wealth, managing risk and making sound financial decisions.

Moving away from a consistent salary often proves difficult for people after retirement, as it can be a challenging transition for many. But billionaire and ace investor Warren Buffett has some advice for those struggling with this transition.

Buffett took control of a struggling textile company in 1965 and transformed it into Berkshire Hathaway, now valued at more than $1 trillion, with annual after-tax operating earnings of about $45 billion. Buffett handed over the CEO role to longtime deputy Greg Abel on January 1 this year, and recently passed on the Chairman role to his son, Howard Buffett.

The 96-year-old Warren Buffett, even after retirement, continues to inspire generations to come. Here are pieces of his advice that can help people struggling with the transition after retirement.

1) The 90/10 investment rule

In his 2013 letter to Berkshire Hathaway shareholders, Warren Buffett introduced his 90/10 investment rule by sharing what he wrote in part of his will. With reference to a cash inheritance going to his wife, he advised his will's trustee to keep 90% of the cash inheritance in an S&P 500 index fund and 10% in short-term government bonds. Buffett believed this mix offers the best balance of growth and stability for non-professional investors. The S&P 500 provides exposure to America's largest and most profitable companies, while Treasury bonds act as a cushion during market downturns.

For retirees or those nearing retirement, such a high allocation to equities, however, may carry more risk, although the strategy has historically outperformed more conservative portfolios. By emphasising low costs, diversification, and long-term growth, Buffett's rule continues to gain attention as a reliable strategy for everyday Americans seeking financial security.

Pay off high-interest debt as soon as possible

Warren Buffett also strongly advised people to pay off any high-interest debt they may have, like credit card debt. In fact, the ace investor believes that paying off your credit card debt is one of the best guaranteed ways to get a return on your money.

If you're drowning in debt, work out a payment plan to pay back your creditors as soon as possible, or the interest will keep piling up. After you're debt-free, make it a point to set aside funds for investments from your income regularly.

Always have a cash reserve

While Warren Buffett is a bullish stock market investor, he did encourage people to hold some amount of cash reserves. "You do need oxygen, and if you are ever without it for four or five minutes, you will learn. And cash is that way. So you always need to have it available, because you do not know what will happen," Buffett told CNBC during an interview earlier this year. He, however, added that while holding cash at certain levels is necessary, it is not a good asset.

The legendary investor likes to keep some level of cash to pay obligations and as "dry powder" for any attractive acquisitions.

Invest in what you know

Warren Buffett has repeatedly stressed the importance of staying within one's "circle of competence." "You only have to be able to evaluate companies within your circle of competence. The size of that circle is not very important; knowing its boundaries, however, is vital."

Buffett famously avoided technology stocks during the dot-com boom of the late 1990s because he believed forecasting the long-term survival of young technology companies was outside his expertise.

Live below your means

Billionaire investor Warren Buffett once famously treated fellow billionaire and Microsoft co-founder Bill Gates not at a fancy restaurant, but at his favourite McDonald's -- and that too using coupons. This famously simple act speaks volumes about the market veteran's frugal lifestyle.

He lives in the Omaha house he bought for $31,500 in 1958. The five-bedroom home is now worth about $1.3 million, but Buffett says he would never trade it because it holds memories of raising his three children. He also avoids splurging on expensive cars. The legendary investor drives a 2014 Cadillac XTS -- complete with hail damage -- because, in his words, giving up half a day to shop for a new car isn't worth it. He even once had a license plate that read "THRIFTY," a fitting symbol for one of the world's richest individuals who chooses to live simply.

"I do not think that standard of living equates with cost of living beyond a certain point," Buffett said at a Berkshire Hathaway shareholders meeting in 2014. "My life would not be happier -- it would be worse if I had six or eight houses or a whole bunch of different things I could have. It just doesn't correlate." Whether it's mansions or sports cars, Buffett avoids major purchases that reflect his wealth, believing they may ultimately detract from his happiness.

Help yourself before helping adult children

Warren Buffett once famously said, "Leave the children enough so that they can do anything but not enough that they can do nothing." He strongly encouraged his own kids to pursue their interests, and all three of them are in different fields and run their own charitable foundations.