Before you build a house, your builder will give you a warranty, promising to fix anything that goes wrong. Beware, "anything" usually means "not everything" and then only if it breaks before too much time goes by.
Typically, they won't cover a whole range of items that shouldn't really be covered anyway. Hardwood floor boards that shrink, for instance, are not covered because, guess what, hardwood floor boards always shrink. They will, however, cover hardwood floors that buckle because hardwood floors never buckle unless they were installed incorrectly.
Likewise, concrete floors crack and that's normal and so that won't be covered either, but if they crack so badly that water seeps in, then that will be covered. Tiles contain imperfections, so you won't be able to get replacement tiles because the current ones have a few blemishes. Problems with the drywall, such as protruding nails, fall into the category of stuff you should notice right away. The builder will typically promise to fix these, but only if you let them know within a month or two of moving in.
These sorts of exceptions make sense. Builders are rightfully trying to protect themselves from unreasonable people who have unreasonable demands.
But warranties shouldn't be so limited so as to protect the builder from reasonable demands. As such, the warranty should provide a full year for all major systems. The furnace should heat the house. The roof shouldn't leak. The basement should be dry. The pipes better not leak. The walls, ceilings and doors should be free of defects.
The warranty, in other words, should protect good homebuyers from bad builders, and also protect good builders from unreasonable homebuyers.