Will I need a camber kit when I lower my hatch? If so just front, rear or BOTH?

 

With a mild drop (down to about 1.5" below stock), you won't need a camber kit if you're concerned about tire life. You'll be able to set the toe to zero, which will avoid eating up the tires (toe angle wears out tires because it's like dragging them a little bit sideways all the time).

The front can usually be adjusted to zero camber without adding a camber kit.

That mild drop will add about 2 or 2.5 degrees of negative camber to the rear, which can't be adjusted to zero without replacing the fixed OEM upper arms with adjustable arm kits. Again, the tires will last long enough with their toe set to zero.

Those two points ^^^^ are good for survivability, and perfectly adequate for daily driving.

If you want to change the handling of the car further, you'll need camber kits front & rear. That way, you can remove some of the negative camber in the rear, and add negative camber to the front.

 

Just the rear