School age children are growing and discovering new interests. You may find that you need to make changes to the schedule based on activities, play dates, and school events. School age kids are likely to ask questions about why the divorce happened, and scheme about ways to reunite their parents. They are also likely to begin thinking about how the parent they are not with is feeling -- worrying about him or her being lonely or sad. Some of this is projection, but some is true empathy. It's a good idea to help your child understand that you always think about her and miss her, but that you are happy with the schedule.
Pre-teens may be entering an age of rebellion (many parents find pre-teens to be as difficult as teenagers used to be perceived as). If they don't like the schedule, they are going to tell you and may act out if they don't get their way. Teens are likely to feel constrained by a visitation schedule. They have their own life -- friends, job, activities, sports, studying, etc. -- and are likely ready to begin having some say over where they are when. The goal is to make it clear that having a relationship with both parents is required. She doesn't get to blow one parent off because she’s mad at that parent.
Throughout your child's life you will have periods of time when he does not want to go on visitation. For many kids, this takes the form of basic whining and difficult behavior. This is normal and is just part of the adjustment process. There are some kids who become radically opposed to visitation and do things like hide under their beds, lock themselves in the bathroom, and so on. Visitation is not optional. If your child cried about going to school would you just give in and say, oh ok, you can stay home? Definitely not. Visitation is just as important as school (more so actually). If your child gets upset, try to find out what the problem is. Often there is something at the root of it -- Dad won't let me play video games, or I'm going to miss Amanda's party. Try to find out what is creating the problem and deal with the problem, not with issue of visitation, because as far as you are concerned, there can't be an issue with visitation. It has to happen.
Some children will say that they want to live with the other parent. Lots of parents get thrown by this kind of statement, when in fact, it's a really normal reaction. Kids often don't know what they really want. When she is with one parent she may feel she wants to live with that parent -- or she may say that she hates that parent and wants to live with the other. Kids are going to be confused. It's hard to have two parents in two places and want to be with both of them.
There are some kids who very strongly feel they want a change in custody. What you should keep in mind is that courts always are interested in children's opinions, however, they are given more weight the older they get. This means that you should do the same thing. A six-year-old who says she wants to live with mommy is much different from a 16-year-old who says the same thing.
Ideally if a change in residential custody is ever going to happen, it should happen by agreement. This is almost never the case. No parent wants to voluntarily agree to let his or her child move out and live with the other parent. In most cases, the court is going to decide a change of custody. If you have a teen who is very certain about what he wants, it is a good idea to listen and try to avoid court. If you protest a change in custody, your teen is likely to feel you are fighting against him personally. I worked with many families of teens where custody fights ended up being personal affronts to the teens themselves. It's quite common for teens to identify with and want to live with the parent of the same gender.