Methods To Quit Smoking

Or did you get a lot more done that you might have once procrastinated on? I quit recently (almost 3 weeks) and have come across this. Curious if anyone else ever had.

My son had a drug test 1 month ago and has to have another this week. This will be 30 days. Can it stay in your system longer than that even if you haven’t been smoking it for 30 days?

Lets say they dont nag about you and youve been together for over 4 months everythings great but your partner acts a little strange towards you everytime you smoke.. would you quit?

Like if I were to say I want to quit next Friday. Since many cigarette companies put specific chemicals and specific amounts of chemicals to keep you addicted to that brand, would changing brands be wise for that weak to sort of lean off of the other addictive substances.
I guess the only problem is you can open yourself to a larger array of chemicals to become addicted to.

Ive been smoking since about feburary. I only smoke about a pack every 4 days, but i have noticed my lung capacity is a lot shorter than it used to be which i know is normal. but if i quit smoking do you regain the lung capacity that you once had or is it damaged forevor?

my friends have a smoking addiction and they want to give up. one of them has tried but found it hard so had to start smoking again. i really want to help them but i dont know how, can anyone help?