In many states, property owners and possessors owe different degrees of responsibility, or duties, to people who come onto their property, depending on how such people are categorized. The law recognizes three main categories of people who might be on someone else's property: invitees, licensees, and trespassers. In states that still distinguish among these categories of people, the legal duty owed to each category is different. It is important to ask an attorney whether these categories and standards of care apply in your state.

Invitees - An invitee is a person who is invited onto property for business reasons, and would include customers of a retail store and job applicants. Property owners owe the highest degree of care to invitees to make sure they are safe from dangers on their property. Under this standard, a property owner not only has a duty to repair and correct known dangers, he also has a duty to reasonably inspect for, discover, and correct unknown hazards in those areas of the premises to which an invitee might have access.

These obligations might simply mean that the property owner or possessor (a business occupying the property) has a duty to take reasonable steps to ensure that the environment is safe for patrons. While there is no precise way to measure what is reasonable, the law defines "reasonable" as what a person of ordinary intelligence and judgment would do under the same circumstances. If a premises liability case goes to trial, it is left up to a jury to decide what is reasonable under the circumstances.

By way of example, it might be reasonable to expect a business owner to conduct regular inspections, maintain, and clean stairwells in his/her property to make sure they are safe. However, it would probably be considered unreasonable to expect a business owner to keep watch all day long to make sure nothing is spilled or broken in the stairwells.

Licensees - A licensee is someone allowed on a premises for social purposes, or for solely their own purposes. Property owners are required to ensure that conditions are safe for licensees, but the level of care owed licensees is lower than that owed to invitees. A property owner is only required to take reasonable care to protect licensees from any known hazards on the property, and does not have a duty to inspect for and discover unknown dangers, as he/she does with invitees.