My best advice to you, a person who may be seeking to adopt a new Havanese puppy, is to do your homework!  Read about the breed and the health issues.  Interview prospective breeders and ask to see proof of current health tests on their foundation dogs.  Ask about how their puppies are socialized, about their health warranty, and go visit the breeder to see the environment where the puppies are raised.  Beware of a breeder who has many unkempt, poorly socialized dogs.  Under no circumstances should you consider buying a Havanese puppy from a pet store or a puppy broker.  Your best source for healthy puppies is the hobby breeder who shows their dogs in conformation events, health tests their foundation stock, belongs to breed organizations, and works with other reputable breeders towards the goal of breeding healthy Havanese puppies, bred to the Havanese standard.  Additionally, a reputable breeder will have a health warranty on their puppies which will tell you, the buyer, what they will do if your puppy develops a serious health issue.  Good breeders do not want their puppies to end up in shelters and they require you to give them first option for taking the puppy back if you can no longer care for it.  A good breeder's commitment to you to take a puppy back should be for the life of the dog!