— Voters in Colorado and Washington state approved legalization in November 2012.
— Sixteen other U.S. states have decriminalized marijuana possession; 23 states and Washington, D.C., allow sales for medical purposes.
—In Colorado, the rules vary widely. Many municipalities have banned recreational pot stores, but not all. Hundreds of older medical-pot stores operate across the state.
—Recreational-sales licences are currently available only to businesses that previously sold medical marijuana.
— Businesses are required to grow their own supply, install security cameras throughout their operations and track every plant, from the soil to the cash register.
—The legal age to buy marijuana in Colorado is 21.
—New cannabis products are proliferating, including vaporizer-style e-joints, cannabis soda and edibles like brownies and pot krispies.
— Colorado introduced new packaging and labelling rules for edible products after some people took ill after eating too much, including children who found their parents' supply. One college student fell to his death after eating a pot product.
— One recent study found a 25 per cent decrease in deaths from painkiller overdoses in states where medical marijuana is legal, including Colorado.
—The black market still exists; illegal dealers sell at about a one-third discount to legal pot prices. Unlicensed sales remain a felony.
—Recreational pot is taxed at over 30 per cent, including state, local, sales and manufacturer levies. In Denver, one gram can cost more than $20. Since medical-pot taxes are far lower, some medical customers have been reluctant to switch.
— Stores run the gamut from being dimly lit and seedy to having chic decor and iPads for menu-browsing.
— Tax revenues have disappointed so far, in part because medical-pot customers are sticking with the old, lower-tax clinics.
— State revenue from pot was about $30 million in the first six months of this year. Pot revenues account for less than 0.002 per cent of the state budget.
— A 2013 state-government survey on marijuana showed a significant long-term decline in use, despite the proliferation of medical pot.
— The percentage of fatal accidents involving drivers with traces of cannabis in their system nearly doubled from 1994 and 2011, as medical pot became available, according to a University of Colorado study.
— Marijuana stores are mainly cash-only businesses, with ATM machines often available on-site.
— It's still illegal to smoke pot in public. Hotel guests who leave lingering traces of cannabis odour in their rooms are subject to hefty fines.