If you don't smoke, congratulations!  If you are  a smoker, now is the time to quite.  That's because, as you grew older, quitting can be more difficult.  You can select your mode of quitting, from Singaporean Ministry of Health:

1.  At Once.  This is the method that work bests.  Most ex-smokers, especially those who were addicted to nicotine, quit smoking this way.  You should try this method first. Go on to the other methods only when this doesn't work.

2.  Gradually.  Slowly cut down on the number of cigarettes you smoke.  Limit the times you smoke,  Don't smoke when you first feel the nicotine craving.  Delay as long as you can.  When you do smoke, smoke only half a cigarette.  Gradually can be done either by postponing or the reducing method.  The postponing method means that everyday, you delay the time you smoke your first cigarette a little later until you can go through the whole day without smoking.  Delay lighting up a few minutes until you can do without that cigarette completely each time you have an urge to smoke.  The reducing method may mean smoking fewer  cigarette each day until you are no longer smoking at all.  The reduction method can also mean smoking less of each cigarette every time you light up, for example, only finishing a quarter or half before putting it out.  Make yourself more aware of each cigarette you smoke.  Each time you smoke, keep a record of it on your reminder list,  your organizer, or your calendar.  See  if you can do better each day by at the end of the day, look at how many cigarettes you smoke and compare it with the previous days.

3.  Setting a quit date.  Set a "quit date" when you intend to get rid all your cigarettes and make changes in routine.  Choose a quit date.  Choose a date on which you will completely stop smoking.  It should preferably fall within a few weeks of your decision to quit.  You could choose a special day such as your birthday or an anniversary.  It's good idea to select a less stressful period within which to quit to make it less difficult for you to cope with the effects of nicotine withdrawal.

On you quit day throw away all your cigarettes, lighters, matches and ash rays.  Make a commitment on that day and each morning after that to make it through without smoking.  Take it one day at a time.  Keep a copy in your cigarette pack or list of reasons why you want to quit, for example, fresher breath, no odor on clothes, and clean teeth.  Review the coping actions you have come up with so that you will know what to do whenever you are tempted to smoke.

knoji.com/smoking-can-shorten-life-expectancy-of-the-smoker-and-nonsmoker-around-him/

Resource:  Woman Today