The only reason there exist such home based meth labs is that other, more preferred, drugs are too expensive, and this due to their being illegal.
Not true. With meth heads - meth is their drug of choice. They make it - just because they can and it's a cheap way to get a whole bunch.
What do you think that someone that likes speed is going to use instead of meth?
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Here's my two cents on legalization of pot. YES - legalize it. End the flow of weed from Mexico and the associated violence. Things right now are changing.
Pot has become so abundent from legal and illegal growing operations in California that it's dirt cheap. A friend of a friend in California is growing it to supplement his income and now he has a hard time selling it (at any price) because there's too much of it around. The going price - $1000.00 a pound for indoor hydro grown high THC content buds.
Don't pm me asking about gettin' some either. Ain't gonna happen. Trafficking drugs is not my bag - Dood.
Leagalize it, tax it and it will become readily available. The demand for black market weed will be greatly diminished and that's where the violence is. The violence, at least with pot, is limited to the people, gangs and smugglers that deal in very large amounts. Take away the motive for illegal profit and the violence and the costs of imprisoning drug offenders will drop cosiderably. Sure, maybe somebody will rob a dispensery but no it's different than robbing a liquor store.
Wiil there be repercussions to society at large? I don't think so. If you want to smoke pot - you can find it - legal or not.
FWIW, I don't think other drugs should be legalized or there be end to war on illicit drugs. It's a plague on society.
Ain't gonna happen. 
Trafficking drugs is not my bag - Dood.