The aim of a custody arrangement is to do what is in the child’s best interest. The needs of a child still in diapers will be very different from one in high school.
The general rule is that a custody agreement should allow the child to maintain regular contact with both parents. Yet, how they do that can vary.
For a baby, it means spending physical time together. On the other hand, teenagers may be able to achieve much of their contact with you through their phones. Many of them spend most of their time talking to their friends online anyway, so not seeing one parent so much face to face will likely be less of a big deal than for someone younger.
The older your children get, the less of a role you play
This is not to say you become unimportant to your children. They still need you. Yet if you think back to when you were a teenager, how much time did you really want to spend with your parents?
You probably preferred to hang out with your mates, or girlfriend or boyfriend. Or to be at sports practice or earning money at a part-time job. The only times you saw your parents might have been at breakfast, when you came home at night, and when they forced you to go with them to visit your gran in the nursing home.
If your teenage child prefers to spend more time at your co-parent’s house than yours, it does not mean they prefer them to you. It may simply be more convenient for them. Maybe there is better public transport when they come home late, or it is closer to the places or people they want to be with.
As soon as your child turns 18, they will have the ability to decide what is in their best interests for themselves. Adapting to their changing needs and wishes sooner can help you maintain a healthy relationship. Forcing them to stick rigidly to the old custody schedule could do the opposite.