Between three and four weeks, every puppy starts breaking in their first set of teeth. By twelve weeks, they should have their full set. Between three and seven months, all puppies lose their puppy (deciduous) teeth and replace them with their adult (permanent) teeth. Bottom line, if you choose to add a puppy to your home, you can expect the first seven months to be filled with teething and chewing.
If family members frequently leave their shoes and socks around, you can expect to find them chewed by your new puppy. It is not that they are being 'bad' or misbehaving, nor that they intentionally seek out your favorite pair of shoes! Puppies explore their world via their mouths and there is an instinctual need for them to chew - it helps to break the tissue and allow the teeth to push through the gums.
If you adopt an older dog and find they are still chewers, have your vet check their mouths. Many dogs retain their puppy teeth and this is similiar to a toothache in humans. If your dog's mouth is in order, then there are psychological reasons for continued chewing - being lonely, bored, stress-related, etc. Substitute a Kong (found readily at any petshop) which can be easily stuffed with bits of cheese, treats, etc. A Kong should keep any dog busy for 20-30 minutes at the minimum.
Regardless of the age, expect chewing to some degree from the puppy stage to their senior stage. The best solution is exercise and substituting appropriate things they can chew on. Even buying toys that resemble human shoes can create a bad habit you don't want to start!
