First, determine the crack's direction. Thin, vertical fractures in drywall or plaster are usually the least worrisome since they're caused by "settling"—the movement of a home's structure over time.
Newly built houses settle more dramatically: the foundation might sink and the frame wood can shrink.
Lack of temperature control may also cause cracks in a property that isn't inhabited year-round, like a vacation home.
These cracks may be readily mended and shouldn't scare you. If your home is spanking new, wait a year before repairing them since you'll likely notice more when the house settles.
Level, horizontal fissures aren't frequently a problem. If they're thin and near drywall seams, it's usually bad taping.
If your crack is angled, jagged, or combines horizontal and vertical fractures in a step-stair pattern, it may be a major issue.