Choosing a pet eventually boils down to various factors such as upkeep requirements and space available, amongst others. These factors are of vital importance in the selection process, so, here are the major ones in detail:

Breed Type
Each breed comes with a unique set of characteristics such as size, temperament, intelligence, and general behavioral features.

Broadly, breeds may be classified as Designer breeds, Pure breeds, Small breeds, Medium, and Large breeds. To determine which is best for you, evaluating your needs and using that as a guide is ideal.

Upkeep Requirements
Some breeds require more frequent grooming than others. Some are high-energy and would need to be frequently exercised.

Others may need special foods kept out of their diets. These are all factors you should consider before choosing a new puppy.

Space Available
This factor mainly plays into the eventual adult size of the dog. If yours is a rural farmhouse with lots of space, you could opt for a large breed or one with lots of energy.

On the flip side, living in a metropolis, perhaps an apartment building, might require a considerably smaller breed size with low energy requirements. Designer breeds and small breeds could be a good call here.

General Needs
In addition to routine visits, how often would the puppy need to see the vet? What are their nutritional requirements? Does the breed require lots of physical attention? These are questions that fall into the general needs of the pup, and one you should consider closely. The idea is to opt for a breed that you can take adequate care of.

Dogs come in various breeds, sizes, colors, temperaments, and have various maintenance requirements. Ensure to go for one that suits your lifestyle perfectly.