The true value of landscape plants, such as ornamental flowers, shrubs, lawns, and trees, cannot be easily translated into dollars. This complicates the development of the tolerance level. In such cases, assessment hinges on the “relative worth” of the plant in its surroundings or on its “aesthetic worth.” In landscape pest management, even the relative value of a planting can depend on such factors as its location in the landscape. For example, in a residential setting, some level of pest damage might be tolerated in a backyard, where relatively few people see it, while the same amount of damage in the front yard often is unacceptable. In golf courses, higher levels of pest damage and invasion are tolerable in the rough areas because the playability of the course is unaffected, while much lower levels of the same damage are acceptable in highly maintained areas. Still less pest damage can be tolerated on the tees and greens, especially on those closest to the clubhouse, where they are played on and seen by more people more often. In sum, pest tolerance in non-economic systems is subjective and varies considerably from one specific situation to another. The point at which the appearance of damage to a landscape or building begins to be apparent and causes humans to be uncomfortable, is the aesthetic injury level. This is much lower than the economic injury level in most cases.