Protect your carries not your useless carries.

If you see your 0 and 8 ADC getting caught because of bad positioning in the late game. Let them die; It is not worth saving them nor risking any lives to save someone whos useless and doesn't contribute anything, you're better off running to lanes and clearing waves so the enemy doesn't push up on you a 4v5. Save your CD's for the people who are actually carrying you that game.

TL'DR: Don't save useless carrys; Protect the ones that are actually usefull.