Bringing a puppy or dog into the home is not for everyone. 
Puppies and dogs are social beings, they need to be part of the family. Sometimes I see people walking dogs and it is clearly a chore for them. Some take their dog out for a functional walk only - as soon as the dog is done his business - back inside they go.
Different breeds have different exercise and grooming requirements. If you are not prepared to teach your long haired dog to accept handling so he can be groomed regularly - don't get a breed which requires it. 
If you are not an active family - don't get a high energy breed such as an Australian Shepherd or Jack Russell Terrier. 
If you don’t want to hear the beautiful baying of a Beagle or will get annoyed when he has his nose to the ground all the time – don’t get one. 
Know your breed and understand their requirements and what they were bred for. Make sure you are willing to provide an outlet for their specific needs.  A digging pit for the Terrier or scent games for the Beagle.
Don’t get mad at your young Border Collie for nipping at your children’s heels as they run and he tries to gather them together. Provide a legitimate outlet.

Don't get a dog because your children or spouse has always wanted one.
Choose the right dog because it's a family decision to welcome a new member into a loving household. Be prepared to nurture, guide and cherish the many experiences you will have for years to come.