I've recently spoken with a few quote unquote experts in credit and credit cards. Although it is wise to pay off your credit cards every month, not carrying a balance to the next month could negatively affect your credit. I've been told that it is best to carry at most 30% of the the cards max. Also once you open a card it is good to never close the account. There are many ways credit cards can help you in real estate. Although I don't advise using them for rehabs per say, If it were my only option to get the job done and I had multiple exit strategies, Id give it a shot. Different people have different risk tolerances. A lot of times you can utilize a 0% interest offer if you were to transfer your balance, usually for a 3% transfer fee. It counts as a pay off and essentially you could have free money for a certain period of time. Usually a year. You have to be very careful though, because it's easy to let things get out of control. If you have the discipline to control your cards they can be a great asset to your tool box. I hope this helps. Have a great day.