Documentation is also important when end users develop their own applications (for example, spreadsheet models or database applications). This self-development places the responsibility for documenting these applications on the same employees who created them. Unfortunately, this documentation task is often overlooked or is performed so poorly that it might as well be overlooked. Such oversight can be costly. For example, time is wasted when other employees must alter the system but lack the basic documentation to accomplish this task. Thus, even if the developer is the only one in the office who uses a particular application, managers should insist that he or she document it—for example, in case of sickness or dismissal.