Habits form all the time, even without us planning them. They form especially quickly as a child grows. Every time we repeat something, do something the same time and receive some form of reinforcement that encourages a behavior the habit is reinforced and likely to stick.
With how habits are formed in mind we should think what habits we are encouraging in our children. Consider what behaviors you are reinforcing or that your child is self-reinforcing, are you happy for that behavior to continue or do you wish it would stop or decrease. If you do want to change think about why and then consider what you can do to make it desirable for your child to change it.
Could you reward desirable activities? Turn the task into a game? Do the activity at the same time every day? Perhaps you could discourage undesirable behavior by taking away privileges? Penalise them through taking away something valuable to them? Delay the grating of an additional privilege?
If you reinforce the behavior with one of or multiple methods mentioned above you can create healthy habits in your child.
Screen time habits from very quickly and perpetuate themselves. The programs, games and applications written for modern computing devices are designed to drive repeated use with increased time spent on them. They are habit forming. You as a parent can try to form healthy screen time habits for your children, teaching them when to use a screen, when not to and how much is healthy to use each day.
Using Pixel Pounds you can use it create a game of when to use a screen, use it to reward desirable behaviour, punish undesirable behaviour. Pixel Pounds can be your partner in creating healthy screen time habits.