There are several underlying reasons why your dog would like to chew though there is no such scientific evidences behind it.
However the following few situations would somewhat describe the conditions under which dog generally fall in love with this activity
If your Dog is a Puppy it is quite likely that like human babies with teething toys, puppies chew frequently as their baby teeth fall out and their adult teeth come in.To ensure that your pup does not Chew your shoes or spectacles please arrange enough chew toys around and check which one he likes best .
Casual chewing by an adult dog is a great enjoyment for her as she develops a very positive association with the chew toys.When they do a good job and you praise them , give them the chew and it builds on his memory . Like human brain dog has got a pleasure centre that lights up when presented with a chew.
Out of sheer Boredom a Dog can also chew anything that gets in front of her as she may not be getting enough mental stimulation. A time with a Doggy playdate or enrolment in some agility training is quite helpful in this regard.
Seperation anxiety is another predominant cause of your dog being too much addicted to chewing and the parent needs to be vary careful in assessing the situation and take corrective steps like not leaving the Dog in isolation for long period of time .
Stress is also another cause that can lead to your dog taking on the chew .However as parent you need to keep an eye on the behaviour so that it does not turn out to be destructive
If the parent oberserve that the dog is destorying the chew then he is extremely stressed but if he is chewing in a relaxed way then this is how it should be .. as dog needs to chew.
However when your dog would just like to have fun or seeking comfort then it is very natural for her to chew her favourite toys In this case, it’s especially important to let her know what things she’s allowed to chew and what things she isn’t through positive reinforcement training