Chewing is a very common but serious problem and can even become life threatening. In puppies, chewing is natural behavior. Even in young dogs that are still teething the red flags should not go up and you should not be overly concerned about the chewing unless it becomes very destructive. In older dogs excessive and destructive chewing is a behavior or nutritional problem. Treating the symptoms can be challenging.
Most older dogs chew out of boredom.
Many time the household schedule and work clashes with the dog's need to play and no longer be bored. In your area many kennels have day care where your dog can go and run and play his or her heart out for a very nominal fee. This activity helps enormously. No dog is a spiteful or vindictive creature. They do not chew your shoes because they are mad at you , or to punish you for something you have done to them.