The right dog is one whose need for exercise, company and training matches what the household can give for ten to fifteen years. Energy and temperament matter more than size.
Breed groups indicate behaviour, inherited health problems vary widely between breeds, and some types of dog cannot legally be bought or sold.
Dogs vary more than any other domestic animal, in size, energy, coat and temperament, and most problems between dogs and their owners come from a poor match. A dog commonly lives for ten to fifteen years, so the choice is worth making slowly.
The Kennel Club, the registry for pedigree dogs in the United Kingdom, sorts breeds into seven groups according to the work they were bred for, which is a fair guide to behaviour.
A pedigree dog's adult size, coat and general character are predictable. The cost of that predictability is that many breeds carry inherited diseases, and responsible breeders test their dogs for the conditions known in the breed.
Crossbreeds, including the popular poodle crosses, are not automatically healthier and can inherit problems from both parents. Their coats vary, and none is reliably safe for people with allergies. Dogs of mixed or unknown ancestry are often robust, and rescue centres are full of them.
Some breeds have been bred for an appearance that damages their health. Flat-faced dogs such as pugs, French bulldogs and bulldogs commonly struggle to breathe, overheat easily and suffer eye, skin and spinal problems; British veterinary organisations urge prospective owners to choose a different type of dog. Very long backs, heavy skin folds, extreme size and miniature size bring problems of their own.
No breed is guaranteed to be safe with children, and individual temperament and upbringing matter more than the label. Dogs often recommended for families are sturdy, tolerant and sociable, such as Labrador and golden retrievers, well-bred spaniels and many crossbreeds. Very small dogs are easily hurt by young children, and herding breeds may nip at running feet.
Whatever the dog, young children are never left alone with it, and are taught not to disturb a dog that is eating, sleeping or in its bed.
A puppy can be raised to suit the household but needs house-training, socialising and months of patient work. An adult dog from a rescue centre or breed rescue has a known character, and many are already house-trained and used to family life. Sources are compared under finding a puppy or rescue dog.
Every dog in Great Britain must be microchipped by eight weeks of age and, in a public place, must wear a collar and tag bearing the owner's name and address.
It is illegal to own certain types of dog without a certificate of exemption: the pit bull terrier, Japanese tosa, dogo Argentino and fila Brasileiro, and, since 2024, the XL bully. They cannot lawfully be sold, given away or bred.
In England, since 1 May 2026, private tenants have had the right to ask their landlord in writing for permission to keep a pet, and the landlord may not refuse unreasonably.