Every household needs rules and routines. Without them you are living in complete chaos. This means you have a set bedtime. Barring very special occasions your children go to bed at the same time every night. As a family you sit down and have dinner together. This also happens at the same time every night. Each member of the family has a few things they are responsible for. Sammy feeds the dog and waters the plants. Beth clears the table and takes out the trash. You have rules. And for broken rules you have consequences. If your children are school-age you have a homework area and routine. Limits are set on TV, video and computer time. Family activities are an important part of your routines.
With that said, this does not mean that there is no give and take in your structure. Flexibility, to a degree, is actually a very important part of parenting. If you have very young children you establish the family rules and routines. After they are established explain them to your children. This does not mean sit your three year old down on the couch and give her a five page list of the family rules. Explain them as the situation presents. For example, at bedtime do the same things in the same order every night. If bedtime is 8:00, at 7:30 run the bath water, when the bath is finished and pajamas are on read a story. At 8:00 tuck your child into bed and say goodnight. By establishing this routine bedtimes become a smooth transaction instead of a nightly wrestling match.
If you are the parents of older children you may want to have a family meeting to establish the rules and routines. You are still the parent, which means you ultimately have the final say, but by giving your children ownership and choices you are telling them that they are important and what they have to say matters. This will go a long way when you have to discipline for a broken rule.