I've never chewed coca but I've never had the urge to keep redosing mainly down to the fact my jaw can start to ache and my mouth ends up really saturated and sensitive, I'd never chew twice in a week, though a lot of somalians in my area are addicted to it. I've never had a noticeable crash from it, compared to say caffeine or MDMA and the like, it's similiar to cactus where it just tapers off, in my experience. I'm in the UK so my khat won't be the freshest compared to phlux's who I'm sure is in Africa, maybe you do get a crash from the fresher stuff I'm not sure.