When to stop?

I made a lightbulb vape the other day, and it's really amazing. It's nice when i want to move around and do things, as i don't really get a body stone. Anyway, it seems that there is always a small amount of vapor left even as the pot turns black; being the stingy person i am, i don't want to let any vapor go uninhaled, so i usually end up with very charred duff. I realize that it's probably worth it to vape it 'correctly,' as in without charring it, so i can make some brownies after a while. So, my real question is: what should completely used duff look like? If you can post pictures, i'd be much obliged.

weed that has been vaped in a proper vaporizer will look like weed that has had the life sucked out of it, brown ashy plant matter, if is grinded before hand which is usually the norm.

As for the lightbulb vape, yeah sure they produce vapour but it tastes disgusting and is a peice of garbage, nothing in comparison to a real vape such as the volcano.

I usually clear the buds after about 2 hits from my pipe vape. The bud should just be brown when your done not charred because you are probably burning some plant material in the process. If you still want to be stingy then save the vaped buds and roll blunts or j.