Broken spokes are almost always a symptom of incorrect and/or uneven spoke tension. Take your wheels to an experienced wheelbuilder and ask them to retension all the spokes in both wheels. Those would be machine-built wheels, purchased from an online dealer, so you can be sure that the wheels were not checked by a human before they shipped it. Keep in mind that just because a wheel is true does not mean the spoke tension is even and that the wheel is strong.

Be aware that not every shop has a good "wheel guy". Call around. And while some people claim they can do it by feel or by ear (plucking the spokes), they should double check with a tensiometer.