How long is the vapor inside a bag good for??

I just bought my first vape (Extreme Q), and I love this thing. I originally thought that I would never use the bag, and always just use the whip, but man I really love using this bag! My question is how long is the vapor good for in the bag? does it start to taste stale after a while?
Another question, If the bud isnt cured very well, or not flushed is there a specific taste that will be there? I just got some Sour D from the same place I always get it from, but this time it has a completely different taste, even in the bong. No big deal as the high is still Sour D fucking awesome, but I was just curious about the different taste this time around. I could just ask the grower if there was something different he did this time around, but I figured Id just post the question here first.

there is a taste difference between hydro grown herb & soil grown when using a vaporizer....... different ferts at different levels will give the herb different tatses too

the vapor will stay good until you use it i'd imagine. im not sure if leaving it in direct light would hurt or not but i cant imagine the vapor only having a limited shelf life unless you have a really small hole in the bag that you dont notice immediately.

right on thanks guys. anyone else get an almost terpintine flavor from sour d??

i have an extremeQ and love it also! the vapor in the bag is only good for like 20-30 mins. at least in my experience it is. forgot to add the reason i know this is i was to fucking loaded and had half a bag left and forgot about it lol came back later about 30mins later, only to find the vape in the bag gone but you can still taste the weed

i'de imagine that it would eventually condensate on the bags surface depending on temp.