Habits are difficult to break and they are difficult to make. The good news is that you can make a new habit but it will take a lot of effort to do. Do not waste time trying to break an old habit because you cannot. I do not believe in breaking habits. You have a habit because it fulfils a need you have. Instead of breaking a habit you should figure out why you have that habit and based on what you find you can make a new habit.
Your body takes about three weeks to get used to something new; it will adapt to new conditions and influences in just three weeks. E.g. if you prefer to drink a certain brand of coffee and you choose to change brand and drink the new brand for about three weeks then you will most likely prefer the new brand over the old one.
It is important, though, that you have your mind set on this change because if you say to yourself: “This coffee really sucks!” every time you drink the new brand, then your mind will focus on the old brand and nothing will change. It is essential that you want the change.
It takes more time to make it a habit
Getting used to something new is not enough to make it a habit. The three weeks as a rule of thumb is to be seen everywhere, but a habit takes the time a habit takes. How long a habit takes to be formed depends on the nature of the habit and the person trying to make the habit. Research shows that a habit takes everything between 18 to 254 days to form. The average is about two months. You can read more about this here.
To make sure that your habit will stick you have to keep your focus and mind set on your new habit for 3-8 months. You have to perform your habit every day and not miss a single day. Habits take hard work, but they are usually worth it if you are trying to make good habits.