Generally people try to quit on their own by either tapering or cold turkey method (abrupt quitting) or home remedies however they bring in lots of relapses and loss of self efficacy in terms of quitting smoking/alcohol/gaming/gadgets.
Since it is addictive, quitting leads to symptoms of cravings, anxiety, irritability, depression, and weight gain. Professional support methods attempt to address withdrawal symptoms to help the client break free of addiction.