with a higher cost anti-theft system, while low-cost items will generally be secured at a lower cost. Insurance companies will often mandate a minimum type of anti-theft system as part of the conditions for insurance. Threshold for theft Anti-theft systems are designed to raise the difficulty of theft to an infeasible (but not necessarily impossible) level. The kind of system implemented often depends on the acceptable threshold for theft. For example, keeping money in an inside shirt pocket increases the difficulty of theft above that necessary if the pocket was on a backpack, since unauthorized access is made sufficiently more difficult. Methods of theft evolve to decrease the difficulty of theft, increased by newer anti-theft systems. Because of evolution on both sides and the social aspect of theft, the threshold for theft is very dynamic and heavily dependent on the environment. Doors in quiet suburban neighborhoods are often left unlocked, as the perceived thresholds for theft are very high. Ease of use Security is often compromised through the lax application of theft-prevention practices and human nature in general. The average anti-theft device does not require any additional effort while using the secured item, without reducing the level of security. In practice, users of security systems may intentionally reduce the effectiveness of an anti-theft system to increase its usability (see passwords). For example, a home security system will usually be enabled and disabled with an easy-to-remember code such as "1111" or "123", instead of a more secure combination. Methods of theft prevention There are a number of general categories of anti-theft systems: Sequestering of valuable items A very common method of preventing theft is the placement of valuables in a safe location. The definition of safe depends on the minimum threshold for theft as determined by the owner. Desk stationery is often considered to be secured if placed in an unlocked drawer away from view, while expensive jewelry might be placed in a safe behind a picture in a home. Raising the awareness of theft Another common method is the alerting of other individuals to the act of theft. This is commonly seen in department stores, where security systems at exits alert store employees of the removal of unpaid items. Older car alarms also fall into this category; newer systems also prevent the car from starting or raise an SOS alarm if ever the tracking device is detached from the car