In our case, we have adopted two beagles and purchased a third, we did research on the kind of dog that would best be for our home. We had a Lab mix who had to be put down because of a brain injury and we had a Golden Retriever, who was just too much dog for the house--great dog, but a big dog.
We studied breeds of dogs we thought we would like and the beagle won out. Almost the next day, the local animal shelter ran a picture of the dog that would become Hannah for us. She was followed by Annie, from the same shelter and then we purchased Sammy at, of all places, a flea market. We were looking for bookcases.
My tips are to consider the following do you:
Do you want and Indoor or outdoor dog or will it be free to live inside and roam the yard for exercise.
Do you want a long-hair dog or short hair dog. Long hair dogs require more grooming and more baths.
Do you want a pet, a hunting dog, a guard dog or what. Beagles are great hunters, but I do not hunt. Beagles are great pets. They are not really guard dogs, but if a stranger approaches the house, they will let you know.
Do you have the room for a dog, the time it takes to train and take care of him and --this is very important--the funds to feed and to see that the dog see the vet when needed. Keeping a dog healthy can be expensive. They can get sick. They can get hurt. They need their teeth clean--can be a $200 job every couple years.
Are you willing to take the time to get the proper tags and make sure your dog wears a collar all the time. I know Lassie never wore a collar, but all other dogs should.
Finally, is everyone in the house OK with the idea of having a dog. If someone is dead set against the idea, you better off waiting until he or she warms up to the idea.
Therefore, consider the older dog at the shelter. They are probably house broken and will only need a little effort to adapt to your routine. They will be grateful. Dogs have emotions--do not try to argue with me about this--I am not changing my opinion. Treat a dog with love and you will have a friend for a long, long time.
If you get a puppy, remember there will be "accidents", puppy teeth are very sharp and they like to explore. Our third Beagle, Sammy came to us as a puppy. A Beagle does not lose his puppy habits until about 3 years old.
Just be prepared.