To prevent failure, don't but them. Simple.
The bean pattern isn't the best.
You lose the ability to adjust the headlights easily.
The housings bounce around a little causing the light to shake, it's irritating on the highway.
Chances are the seal will slowly deteriorate and you will get water inside, plus the halos burning out.
You will be BEST doing a projector retrofit, it will look 10x better and cost about the same. You will still have adjustable head lights plus the light out put will be a night and day difference. Www.theretrofitsource.com