It can get fairly complicated when trying to answer this particular question because everything revolves around understanding exactly how much and what type of damage you've managed to inflict on your body.
Normally a person will be smoking for quite sometime before he or she begins feeling the ill-effects caused by their addiction and then subsequently start asking the question "if i kick the habit, will the harm that smoking has done to me in point of fact heal?"
It really depends; what amount you've been smoking, for how long and what type of cigarette or tobacco you've been smoking - the amount of harm that you've inflicted on yourself will therefore be the determining thing on how long it'll take your body to fix itself.
A great deal of any damage you inflict upon yourself by breathing in that poisonous smoke can be reversed but is very much dependent on other things that determine how long it will take for the curative process to work i.e. Your age, your general physical fitness, your diet etc.
This really all is pretty much common sense. I mean if a person had been smoking 10 cigarettes a day for a year previous to quitting he or she will apparently have suffered much less harm than a person who spent the last 30 years smoking 40 every day.
Let's not now forget the permanent damage caused by prolonged heavy smoking either - lung damage is most certainly the most usual type meaning that if you've smoked way too much for way too long then the sections of your lungs damaged by smoking will simply in no way recover.
Permanent lung damage can be classified as severe or only very mild, but it'll definitely be an issue you'll have to forever live with.
Having said that, you also need to know that 'every cloud has a silver lining' because generally speaking you'll very definitely and very quickly notice a strong recuperation of your healthiness and vitality - 2 to 3 weeks often appears to be the time usually bandied about.
You shouldn't take this to mean that your self-imposed damage has completely righted itself yet, but it does mean that at least the healing process has started and is possibly even a good way to completion - it can in fact take anything up to ten years for your damaged lungs to return to their prior-to-smoking condition.
I've no doubt that you now understand why you need to stop smoking ASAP if you want to give your damaged body a passable chance of recovery and dodge everlasting or potentially life-threatening harm.
In summary; it doesn't matter how long or how much you've been smoking, you can improve your health and even though you're bound to find it a little tough at first, being able to kick the habit is much easier than you think