Looking to Buy a Puppy

Probably the best season to be looking to buy a puppy is spring. Once he has been vaccinated and can be trained out of home. Do not choose a puppy in the summer when you are planning to go out on vacations, cause his training will be interrupted, and most of the canine residences will not accept a non vaccinated animal. It would also be traumatic for the dog to be moved from one house to another so quickly. Its also is not recommendable to buy a puppy at Christmas, cause in these dates the house is in disarray and full of guests, with no time left to take care of him. It is no coincidence that most dogs are abandoned or rejected by their owners in this season of the year.                                   
Which breeds demand more attention than others?