RCA wire length?

I am putting my amps on the rear shelf. Wondering what length of RCA cables would be the best? I don't want them too short, but I don't want a ****load of extra left over!!!!

By the way that is going into a 2002 ss.

i used 17 ft. that allows you to run into the rear well and up under the carpet

my install kit came with a 17ft cable and it worked just fine. i had plenty of room to work with and not too much left over.

Thanks for the help guys I ordered a 6 channel set of 17 ft. cables.