It's better to quit doing it while you can and able to do it, rather than quitting because you are not strong enough to do it or due to doctors recommendations.
life is a struggle , everyday you ask your self the same questions:
1- why am i here
2- where was i before i came here
3-when and how will be my final destination
All humans have the good and the evil inside them, if you water your good it will grow and if you water your evil it will grow.
we all seek fast and easy pleasure of life such as (sex, funds....) but if you think for a moment about your past and your decisions and behaviors i think you'll be regretting most of them if not all.
Like when you get sick because of smoking and now you'r suffering you'll be regretting all the past times you smoked in, those days are gone but the effect of smoking stays.
Like when you cheat your beloved and loose her for doing such thing, you'll feel remorse, the joy is gone but consequences gonna carry on.
On the other hand is you don't seek fast gains and pleasure:
Like when you buy shares in the stock and just leave it for ten years, it will grow but if you kept trading every day seeking fast profits you gonna loose it all.
Like when you take care of your health you'll grow old healthy.
Like when you'r faithful to your beloved you won't feel remorse of any thing you've done in the past and this feeling is great.
Quit bad things while you can with your own will.
Every day is a chance for you to prove that you deserve what is waiting for you.