Dogs come in all shapes and sizes - the UK Kennel Club recognises 221 different pedigree dogs, from Affenpinscher to Yorkshire Terrier (there are sadly no dog breeds starting with the letter ‘z’!).
Then there are all manner of crossbreeds, from so-called ‘designer dogs’ to lovable mongrels.
Each has its own list of positive and negative attributes, and it’s important to take plenty of time to think about what breed will fit into your lifestyle the best - for instance a smaller dog if you live in a flat, or a hypoallergenic dog if the mere mention of dog hair makes you think about sneezing.
There is even scientific research to guide you, in particular psychologist Stanley Coren’s groundbreaking book The Intelligence of Dogs.
And one thing you might like to consider is that some dogs are naturally better guard dogs than others.
Labrador Retrievers may be affectionate and popular, but they’re likely to welcome a burglar like a long lost friend - particularly if they come armed with a few tasty sausages.
On the other hand, other breeds are naturally suspicious of strangers, ever-vigilant and have the potential to be ferocious if challenged or confronted. It also helps if they look a bit scary.
Here are the 24 best and worst breeds of guard dog.
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9. Beagle
Beagles are many things - curious, fun-filled, gentle and adorable - but they simply aren't territorial. Add in their default setting of 'friendly' and they barely even guard their own food. | Getty Images for Westminster Ken
10. Cavalier King Charles Spaniel
Bred for companionship and cuddles, not protection, the Cavalier King Charles Spaniel is affectionate and trusting. They completely lack the size, aggression, and territorial instincts necessary to deter or confront intruders. | AFP via Getty Images
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11. Irish Setter
Your best hope with the playful Irish Setter is that it might tire out an intruder with constant demands for games. It's a wonderful family-friendly breed but has incredibly low levels of aggression. | Getty Images for Westminster Ken
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12. Havanese
Many small dogs are quite effective at guarding homes, being vocal and potentially aggressive. That's not the case with the Havanese which is one of the least yappy small dogs. It often seems their sole aim in life is to find a lap - any lap - to curl up in. | Getty Images