Other bad habits have life-shortening consequences. Eating the wrong foods and failing to exercise will threaten your health and longevity. Smoking and abuse of drugs or alcohol are two other serious, life-threatening bad habits.  Compulsive shopping is another bad habit that can jeopardize your financial stability and ultimately erode your mental health. Even being a fashion victim by wearing the wrong shoes can increase your risk of chronic disability. Though to change some bad habits you may need professional help, as I discuss below, by understanding the basic principles of behavior change, you can get a head start on the process.

Step 1. Decide that you really want to change and convince yourself that you can

You can only change what you decide you want to change. All psychological models of change emphasize the importance of commitment as a necessary first step. If you don't see a problem, you won't work on changing your behavior. The more honest you are with yourself about the nature of your bad habit, the more likely you will be to start on the path toward change.  You might want to start by keeping a log of your bad habits- how often you've been late, overeaten, smoked, lied, or drank to excess, for example. To help motivate yourself, a frank conversation with the people closest to you may prove valuable.  People who care about you can give you the mirror you need to see your problematic behaviors for what they are. 

Once you've decided you want to change, convince yourself that you are able to achieve your change goals. You need to strengthen your sense of self-efficacy, or belief that you can accomplish what you want. Seeing other people change successfully is inspiring, but you need to see yourself as having what it takes to make those changes in yourself.  As you go through Steps 2-4, you'll build your self-efficacy and become even more likely to succeed.

Step 2. Try to gain insight on what's causing the bad habit

Once you figure out your inner motives and the external incentives that are driving your bad habits, you'll go a long way toward changing them.

Take a good hard look at the situations that lead you to commit your bad habit. If it's lateness, as Galanes suggested, you may be trying to control the lives of others by setting the times that you (not they) want to meet.  It's also possible that your behavior is motivated by a kind of self-defeating need to undo yourself, or what psychoanalysts might call "neurotic behavior." Do you unconsciously try to thwart your own success because you don't feel you deserve to do well in life? Do you fail to engage in good health habits because you don't think your body deserves to be treated properly? Are your addictions perhaps motivated in part by some need that you have to fail or shorten your life?

These sorts of inner motivations may interact with influences that are acquired through specific experiences.  Everyone responds to reinforcements-- the rewards that strengthen our behaviors. Some bad habits just feel good, so we keep repeating them. They may also make our other problems, such as stress, temporarily go away, and this relief becomes another source of reinforcement. Social rewards add to the mix. If your friends don't complain when you're late, act in overbearing ways, or commit social improprieties, you don't see any real reason to change. In fact, the behavior of other people might keep your bad habits going. You're late to a meeting, and everyone rushes to fill you in on what you missed. Now you've gotten some attention for your movie-star like dramatic entrance.

          By figuring o

ut what's causing the bad habit, you can also work on deciding how to manipulate the outcomes of your behavior. Take the outcomes that are reinforcing the bad habit (attention, pleasure, excitement) and then use them to reward you for the behavior you want to acquire. Do you savor the attention of being late? Figure out other ways to be noticed. Does that fried food just taste too good to give up? Find ways to get satisfaction from healthy eating. Even Bill Clinton, a well-known gourmand in his younger days, says he feels better than ever on his new vegan diet.

Step 3. Set reasonable goals at first

Your bad habits have taken years to establish themselves. You're not going to throw them off in an instant. Decide on a realistic schedule that will work for you based on goals that you believe you can meet.  Overcoming your sedentary lifestyle is a good example of how you can proceed through this step. In the first place, don't think that you can readily go from zero days of exercise a week to seven. You'll be bound to fail and then use your failure as proof that you can't change. Instead, work out a schedule of times to go to the gym or on a run that will readily fit into your existing schedule. Start off slow (two or three times a week), and gradually increase until you're at the level recommended for your age, gender, and family history.

When it comes to a social behavior such as being chronically tardy, your ultimate goal of never being late may also be hard to achieve in one step. If you're typically running 20 or 30 minutes late for your appointments, set a preliminary goal of "only" being 10 minutes late (still annoying to other people but not quite as much).  It's unlikely you can change completely right away if this is an ingrained habit reinforced by others and caused by some self-defeating tendencies. Cutting the tardiness factor by half is a good start.

Step 4. Measure your progress and don't be discouraged by occasional slips

If you're going to reach your ultimate goal, you'll need to know how well you're doing on achieving the reasonable goals you've set as first steps. This means that you have to keep a diary or journal.  In the case of exercise and weight control, for example, you can take advantage of online recording programs that also give you tips that adapt to your record of progress. There are certainly "apps for that" which can make your record-keeping easy and perhaps reinforcing in their own right.