An action becomes a habit when it becomes a regular pattern. A one-time indulgence can become harmful only when it features regularly enough to have a long-term effect. Likewise, healthy habits are useful, but only as habits; going to the gym once isn't going to turn you into The Rock.
The habits we acquire and lose over time show our personal development. Sometimes these habits are positive habits, and sometimes they are less helpful, but good or bad, these habits say something about where we are in life and what we're up to. The bad habits of youth could give way to healthy adult habits, or they could give way to bad habits that, while more mature, aren't better so much as they are different.
Habits are much of the pattern that is life. How you choose your habits is a matter of character and circumstance, both of which are a product of your life and where you are in it. A young person is unlikely to make sure their cane is positioned within arm's reach when they climb into bed, for example, only because most young people don't require canes to get around.
We have a pretty good handle on the habits that characterize the stages of life, and we are sure that if you tell us a bit about your life, we can guess your age. Care to give us a try?