The ongoing problem with broadmites is, now matter what method you use to treat, they keep coming back, because they are not only on your plants, but everywhere in your house/yard, etc. They WILL come back. I don't think there's anyway to stop that. When I was treating these with Avid, etc., I had huge trees, 7 feet tall, and it was a royal pain in the ass spraying large plants. Had to drag each one outside, spray it down, trying to make sure not to miss a spot (not easy with trees), then set it down in a separate area, drag the next one out, and on & on. It was extremely tedious and time consuming work, that had to be repeated every three days as eggs are always hatching and more mites continuously entering the room either from outside or from elsewhere in your house through the ventilation ducting, etc. Not to mention the toxicity of the chems, and need to wear protective gear at each spraying. So I found the heat method much easier for my particular situation, large trees in a vertical setup. Much easier for me to just turn the heat on and leave it for an hour, than to spend hours spraying toxins. Not to mention that some folks just don't want Forbid on their meds. Everyone's situation is different, but for me, the heat was much easier & more effective. If you are in a cold climate, I don't think these are as big a problem. If you are in a tropical climate, your problem is magnified, because they are all over the place outside, and continually re-enter your grow space.
