I like to run mine pettty hot, and get really dark ABV, no problems with the oil left behind, no sings of combustion, just really dark toasty herbs left over. If you combust, you will have ashes, and get yellow smoke instead of vapor, it's petty noticable, might leave a bad taste to the reclaim if it happens, but unless that in itself is a deal breaker, I wouldn't say it ruins anything else. Unless that's all you are diong is combusting with it over and over, then it would just build up the usual bong resin we are familliar with from combustion days. That is my take on it... I found between 30-40 watts is a safe range for my herbs, but prefer it closer to 33 or 35, once in a while it jumps up and get hotter, by a few watts, not stable, but close enough that I can work around it.