Some breeds have so much energy and are so active that if you do not give them a sufficient workout every day - a long walk and hard run - their pent up energy will quite likely manifest itself in destructive behavior.
So keep in mind that if you choose a breed with a long coat you will either need to get it clipped regularly if you want to avoid brushing it so much, or if you choose to keep it long or even medium length you will have to brush it every day.
When large dogs eliminate, they eliminate a lot more than small dogs. More goes in and more comes out of large breeds. Which is something to keep in mind if your dog will live inside - especially if you live in a high rise apartment and he will have to be litter box trained (there is always going to be more to clean up).
Keep in mind that large dogs are more expensive to keep. They eat more food, which costs you more money. Tick and flea preventives cost more for large dogs, as do other mediations.
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