I agree with you both JoyJoy and Ima, if you have the self control to always to pay off CC's each month in full then there is no harm in having them...
I am just giving another idea about how some folks might want to insure they never get into CC debt again...don't have them and don't need them!
I just prefer to live a life without CC's...my good old debit card that is linked to my checking and backed up with my savings is all we will ever need. The "Nickels" and "Dimes" (really Pennies) that I could "make" using a CC holds no interest for me (pardon the pun). I am focused on other areas to build my wealth... Nothing wrong with it for you, but its just not for me.
To each their own and now matter how you slice it we are all doing much better then most and should be very proud.
