Group 1 - The article discusses five types of debts that may not need to be repaid, highlighting the importance of understanding legal rights regarding debt collection [2][3][4] - The first type of debt is those that exceed the statute of limitations, which is three years for ordinary civil cases, meaning creditors lose the right to pursue repayment if no legal action is taken within this period [2][3] - The second type involves debts without clear evidence, such as verbal agreements without written documentation, making it difficult for creditors to prove the existence of the debt [4][6] Group 2 - The third type pertains to illegal high-interest loans, where any interest exceeding four times the Loan Prime Rate (LPR) is considered invalid, allowing debtors to refuse payment of the excess [7] - The fourth type includes debts that are legally exempted, particularly under the personal bankruptcy system, which allows debtors to discharge remaining debts after certain procedures [8][10] - The fifth type involves unjust enrichment claims that exceed the three-year statute of limitations, meaning that if a debtor is not pursued within this timeframe, they are not obligated to return the funds [11] Group 3 - The article also provides recommendations for lenders to protect their rights, emphasizing the importance of written agreements, maintaining evidence of collection efforts, and using formal channels for transactions [13]