The American Academy of Pediatrics makes the point that children in home care watch an average of 2.4 hours of television each day, while those in care centers watched only 0.4 hours. It also found that pre-school children at home are most often looked after by someone other than the parent. One interpretation of this could be that even when they have someone else looking after their children, parents should monitor and control the hours spent in front of the TV.
Think of ways to make not watching TV more enjoyable than watching it. For example, consider making sure that there are a lot of other options in the room such as toys, games, books and comics. Spend time in the room where the TV is located and encourage your child to be interested in playing with you rather than passively watching the television. Children are incredibly inquisitive and you can stimulate this in a better way than letting them watch to much TV.
Impose some rules -- but remember that the best rules are set by example. One obvious rule is that there should be no TVs in your kids' bedrooms. Another is that neither you nor they should watch TV during meals -- make these family occasions. Separate homework from viewing time. Think about the rules that your parents set. If they restricted your use of TV then follow the examples that you were set.
There are many ways to limit TV for adults as well as kids. One suggestion is to find other things to do. Another is to check the TV listings and choose what you are going to watch, rather than simply mindlessly surfing all night. You could also use TV as the basis for a wider lifestyle change so that you can fit it into a routine that includes more and healthier activities.