Battery life it's good, what can I say to give realistic view of it? if I tell you that @ maximum power it stays on about one hour, it doesn't tell much. And about number of "typical" vaporizing sessions I haven't been counting. But let's say that if it takes little bit over 2 minutes to get to temp, and it's maximum power then, and the way it hits, for most people it will not be on that much after warm up. I would say that the battery life is good.
And the batteries are not so costly, so people can have another set ready to go, it takes maybe 8 seconds to change batteries. Actually I was thinking, might be best to include 2 sets of batteries with it, so that it feel more complete. Never need to wait for charging when another set can be always full. And another advantage with this is, that as I feel the actual vaporizer is very robust, like my friend said, "feels you could use this as a hammer", and the electronics are sealed, there are no mechanical buttons, so it is really hard to break it I think, only the glass tube might break if you hit it somewhere, but since it is 2mm thick round glass it doesn't break that easily.
And it can be also shorter if preferred, near the level of front panel to make it even less probably to have any accidental contacts. so the batteries are the thing that wear out finally but it really doesn't matter since you can easily get new ones. The halogen bulb wears naturally but can be easily changed, and in normal conditions, in my experience, should work anywhere from 1 to 3+ years and for sudden drops or weaker bulbs we always deliver one extra bulb anyway with our vaporizers.
Yes it is possible to reload it while it is hot, but it requires you to overcome the obstacle of very hot herb chamber. I have done it, on table, just to release the chamber, and let it roll on your table and fill it up. But really it is hot, so if really a reloading while it is hot is necessary, some tricks are necessary to not burn your fingers.
Herb cooking while idle depends again on the settings. No, herb will not need to get cooked even if you like to ide longer times. For example, when I want to be sure that herb will not get cooked even if I wait longer times, I just set lower basic power level, and just boost a few extra seconds before taking a hit, to get to the optimal temperature. you just learn it quickly to feel how to get what you want from it, that's all I can really say.
The vaporizer does have signal lights. It shows when your gestures to turn it on are registered, it shows when it is warming up, it shows when it is ready and on, it shows when you boost, and it shows power level you set, and when you are in setup mode for warm up time. It's all very clear and simple.