Make sure that the shelter you adopt your pet from has a good reputation and really looks after all the animals it claims to be helping. If you are unsure, stick with bigger charities such as the RSPCA or the Cat Protection League. When you approach the organisation and spot the pet you think is right for you, ask questions about its history. If you get no satisfying answer on this pet's background, especially one that is capable of harming a member of your family, then you are taking a risk. For example, a dog that has been mistreated or suffers from severe behavioural issues may be a threat to a child who is not aware of how to handle another living being. Children are particularly at risk because if their size but this consideration applies to adults as well. So if the organisation cannot guarantee that an animal has never been aggressive towards humans or other pets, best to avoid that pet. A girl in Leicester was killed by a dog from a rescue centre whose history was unknown. You can read about it here. Moreover, not knowing the history could prevent you from knowing if that pet may have congenital health issues. Although all animal rescue organisations will vaccinate their pets, they may not know what diseases they were exposed to before making their way in the shelter.
If you decide to purchase a pet, you will still need to ensure you refer to a reputable breeder who is able to tell you about the animal's history and answer all questions you may have regarding its temperament.
When you buy a pet you can choose from a greater range of animals and if it is a young animal it should not have had any history of being mistreated or of having developed bad habits.
If you buy a pet from a breeder you can ask them what genetic diseases it has been tested for. You can do your homework on the breed and find out what genetic conditions you may need to be aware of. Furthermore, you should be able to view the parents ad see what kind of temperament they may posses. If you buy a pet from a breeder who is selling purebred animals, you should be able to ask proof that the dog or cat is in fact a pedigree animal. Certain features are associated with particular animal breeds only, especially in relation to dogs.
The greatest danger when buying a pet is if you are tricked into buying a pet from a rogue dealer, such as a puppy farm or an illegal importer. Rogue pet sellers are only interested in money and not in the welfare of the animals that they sell. The price of a pet from a rogue dealer might be less than from a reputable breeder. That is because a reputable breeder spends a lot of money on genetic tests and ensuring that the young pets are healthy and free of genetic disorders. Rogue dealers can produce high numbers of puppies or kittens with little cost. Animal lovers know that a pet is a living being that needs care and affection, not a toy that can be used and discarded when the novelty wears off.
One benefit of buying or adopting a fully grown animal is that you will know the actual size before taking it home rather than being surprised when buying a puppy. A good example is the case of baby pot belly Vietnamese pigs purchased and then grown into very large animals leaving owners unable to keep them in their homes. When you buy a young animal you can not be sure what size it will grow into. If the breeder is an expert and can show the pedigree of an animal then you can be fairly sure what size it will be. If an animal is the result of an occasional mixture of breeds then you have to take your chances. This applies to the pet's size as well as personality: if the person selling doesn't know the animal's background then even the personality traits will be unknown.
Just because an animal has a full pedigree there is no guarantee that it will be completely free from health issues. Before buying or adopting a pet, you must be sure you will be able to afford any vet fees for the rest of its life. This is why, more and more people opt for pet insurance which can assist with sudden large vet bills outside (excluding the regular checkups). Regardless of how healthy your pet is, there is always a chance that it may have an accident or pick up some serious infection.
Whether you buy or adopt make sure that the people you obtain your pet from are knowledgeable and genuinely interested in the welfare of the animal rather than making money.