Certain types of surety bonds that do not easily fall into natural and well-defined classifications are considered more difficult to place than normal bond classes. These are classified as miscellaneous bonds and collateral is required when they are written. Because of the frequency of use and the amount of premium volume, lost instrument or lost securities bonds are the most familiar of the class. Other types of miscellaneous bonds given special treatment by surety markets are income tax bonds, which are given to guarantee payment of federal income taxes due; subdivision bonds that guarantee that certain property improvements, such as streets, sidewalks, and sewers, will be constructed by a subdivision developer; bonds that guarantee the performance or long life of a certain product or service such as long-term guarantees of roofs and roofing materials; patent infringement bonds; blue-sky bonds; self-insurance bonds; and numerous other "once-in-a-lifetime" specialty bonds that require individual underwriting judgment.