A lot of the negative feedback you’ll see for mosquito traps is because new owners didn’t use them properly!
Mosquito traps don’t REPEL mosquitos, these machines ATTRACT the mosquitos and then kill them. It also takes a while for them to lure and kill a large local population. Buying a mosquito catcher in the afternoon and putting the unit in the middle of your big neighborhood barbeque that same night is a sure recipe for turning your party into an itchy, buggy disaster!
These mosquito machines should be placed a good distance from where people are congregating (ideally, 35′ or more), preferably upwind. Place mosquito traps on the perimeters of your yard, not in the middle of your activity area, and set them to run 24/7 or at least daily during peak insect activity times (dawn and dusk) at first. After several days they will have begun to kill off the existing colonies and you’ll be well on your way to a mosquito-free yard! Source