Adding Air Lift bags for the rear, should I install new rear leafs too?

So about two years ago, I replaced what I believed to be the original OEM rear leaf springs with General Springs HD variety for a 2002 4x4 Tacoma. They are unfortunately already beginning to sag. I have a set of Air Lift bags to throw on to help out, and checked out a couple threads with some install advice.

My question; should I just add the airbags and run it or should I buy new leafs for the rear as well?

 

I would not use air bags to alleviate the flattening of the springs and level the truck.

If the springs are flat and rear is sagging, I would replace springs. I would use bags for towing and extra weight loads