In general, duties of a property owner do not extend to making the sidewalk perfectly level or to remedy trivial defects; a reasonably safe sidewalk condition is all that is necessary. Slight variations in grades, will not, as a matter of law, sustain an action in negligence. Remedy or repair is not required until the break or imperfection becomes patently dangerous. Crumbling cement or cracks and holes in the middle of a sidewalk which create a tripping hazard are the types of defects property owner would be wise to repair.Also, where persons are permitted to use a path directly over anothers property for some time, and, although with full knowledge of such use, no objection is made by the property owner, the owner owes such persons, known as a licensee, the duty of ordinary care, and is bound to see that there are no dangerous pitfalls, or, if they exist, to give reasonable notice or warning in order to avoid injuring those in the habit of using the pathway. Landowners are not subject to liability for conditions that are completely obvious. A danger is deemed to be "obvious" when both the condition and the risk are apparent to and would be recognized by a reasonable man, in the position of the visitor, exercising normal perception, intelligence, and judgment. However, keep in mind that conditions that pose no basis for liability during the day may become otherwise if covered or obscured.