Normally the front brakes wear first, so rear brakes wearing faster is a red flag worth understanding. A few specific things cause it. Here is why your rear brakes might be wearing faster than the front.
It is not the usual pattern
Front brakes normally do most of the work and wear first; see why front brakes wear faster. So rears wearing faster means something is shifting more load to the rear than normal - worth investigating.
Electronic brake distribution on modern cars
Many newer vehicles use electronic brake-force distribution and stability control that apply the rear brakes more actively, so rear pads can wear surprisingly fast by design. On these, quicker rear wear can be normal - check what is typical for your model.
A dragging rear caliper or parking brake
A sticking rear caliper or a parking brake that does not fully release drags the rear pads constantly; see sticking caliper and one brake running hot. Look for a hot rear wheel or uneven side-to-side wear.
What to do
Check for a dragging caliper or parking brake and confirm even wear side to side; see wear patterns. If it is just active EBD, keep an eye on the rears. Fit quality pads and hardware.