Almost every home Houspect inspects has cracks in the walls. Most of these cracks will be simple surface disturbances of the plaster caused by the property expanding and contracting naturally. New homes in particular can be plagued in the early months of occupation by minor cracks caused by the home settling. For the most part these cracks are harmless and can be easily repaired.
However, if the cracks persist and reappear or get noticeably wider, it is worth getting to the bottom of what is causing the problem. Large cracks may signify serious problems such as corrosion (of wall ties or lintels) or foundation movement, subsidence, heave or settlement.
If you are concerned about a crack, measure how wide it is in a few places, and mark where it terminates. If after a few months the crack gets wider or longer, call a professional building inspector and get a detailed report on the condition of your building.