Whether or not you should apply to the court to enforce the order depends upon whether you are adversely affected by the breach, and whether you consider that enforcement action would be in the best interests of the child(ren).
Obviously, if you are the parent who was granted contact by the order and if you are unable to have that contact because the other parent is in breach of the order, then you may have to apply to the court to enforce the order.
On the other hand, if the contact was granted to the other parent and they are simply not having any contact then there is little you can do - the court can't force a parent to have contact with a child. If the problem is that the other parent is not keeping to the terms of the contact order, for example regularly returning the child(ren) after the time specified in the order, then you may have to return the matter to the court, possibly for the terms of the order to be re-defined.
If you are considering making an application to a court to enforce a contact order you should first seek the advice of a specialist family lawyer.