If you know that some of your habits, after a passage of time are going to harm you, you should take precautionary measures to stop them there and then. Precautions don't give your problems a chance to arrive.
"Stop smoking" are the words many people get irritated of. "It's cool" you reply. Knowing that it is bad for your health.
Precaution is far more easier than curing it. Curing costs a lot of money, consumes time and ends up in financial crisis and depression. It is easier to work now and take precaution than to fix the damage later.
Not everything can be learnt after the milk has already spilled !!! What's the harm in being a bit alert. After all its all about your life and people around you.