Shedding vs Non-Shedding

If your mind is set on one or the other based on choice of breed, then you will get either a shedding variety or a non-shedding dog.  For those who are considering a dog for the first time though, this is a choice that matters.
There are degrees of shedding dogs.  Short hair or long the amount of hair and thickness of hair varies between dogs.  For example a Labrador does not shed as prolifically as a Samoyed because of what it's coat is designed for.  A Samoyed comes from Siberia where it lives in harsh winter conditions.  When it sheds it sheds volumes.  It is in fact a high maintenance dog which requires brushing often. 
I remember a friend owning one and with every brush stroke handfuls of hair would be removed.  Conversely a Lab requires less attention.
Hair will inevitably be shed and require extra work if in fact you allow the dog indoors.  The hair will weave itself into furniture seats, your sock and often is impossible to remove.  This means constant vigilance on the owners behalf in house cleaning, training of the dog to sit or sleep in specific areas.
Non-shedding dogs come with their own set of concerns.  Grooming becoming the most important concern.  Your Shih Tzu variety will require regular brushing and of course haircuts.  Most people will take their pet to the groomers ever 6 weeks to avoid matting of hair. 
These dogs do not shed hair, however, they like humans, lose hair, and will require regular brushing.  The longer the hair becomes the more work it becomes.  My dogs are not show dogs and in the winter we allow the hair to grow.  When we go into the woods for a walk, the hair gets wet and muddy requiring a bath when we return home.
Medically speaking, if you are prone to allergies, non-shedding dogs are the correct choice because these non-allergenic dogs do not shed releasing as much dander into the atmosphere as do their shedding counterparts do. It is the dander that most people are sensitive to.
Obviously, the choice is yours, the amount of labor depends upon the style of coat.  Both types have maintenance requirements and within that there are the sub groups based on size of dog, where the breed originally lived, what their coat was designed to do, that will determine the level of work.