The law of United States protects the interests of both borrowers and lenders. It is in public interest that all lawful borrowing should be repaid. So, if you have taken a loan and are unable to repay it then the lender has been provided with the legal right under the Federal law to take you to court and file a lawsuit against you. But there is a time frame within which the creditor has to file a law suit. This is called statute of limitations. The period starts from the time you have stopped making payments of monthly installments of your loan. However, one must remember that expiration of the statute of limitations period does not mean that the creditor cannot file a lawsuit against you. But the lawsuit can be dismissed by the concerned court on this basis on the plea of the defendant.
The statute of limitation only prevents lawsuits to be filed against you but in no way prevents other types of collection methods employed by the debt collector. The creditor can report your case to the credit bureaus and it will be reported in your credit report. All lenders access your credit report before approving loan which means that you will have a default in your credit report and therefore will not be eligible for any loans from any lender for many years. So, in short, your trouble does not end with the expiration of statute of limitations for debts. The creditor or the collection agency can continue calling you or visiting your home or office for the recovery of the amount owed. However, there is a 'cease and desist' provision under Fair Debt Collection Practices Act which instructs third party collection agencies to follow certain norms. So, it is best to repay the debts and in case you are unable to do so for any reason such as loss of income or job then talk to the lender and create a mutually agreeable debt repayment plan.
However, if you have made any written promise to the lender after delinquency of the debt then there are separate provisions with the law to deal with such matters. You can consult with a credit attorney to find out about the legal process to be followed in such cases and to know your rights. There are many attorneys in United States who specialize in credit related cases and provide counseling and advice to borrowers.