Always good to have longer than you need. If you ever decide to move your amp to the rear of the vehicle or get a different amp with rcas on opposite side etc... you will be able to without buyin new rcas again. But I recommend knukonceptz. They make great quality rugged rcas that fit very snuggly and wont slip out. They look awesome too. I just bought a 2 channel and 4 channel set for $62.00 shipped. They are 19.7 ft each.