Revolving credit is a flexible financial instrument where a credit line is extended to a user, allowing them to borrow up to a set limit and repay, with the credit becoming available again. Common types include credit cards, personal lines of credit, and HELOCs. Proper management can improve credit scores through on-time payments, credit history, and credit mix, while poor management can lead to high-interest debt and damaged credit. Advantages include flexibility and control over funds and repayment, but drawbacks include high interest and potential for accumulating debt.