A habituated systematic process becomes a device that the person can use with ownership for effective time management. A task list (also called a to-do list or "things-to-do") is a list of tasks to be completed, such as chores or steps toward completing a project. It is an inventory tool which serves as an alternative or supplement to memory. Task lists are used in self-management, business management, project management, and software development. It may involve more than one list. When one of the items on a task list is accomplished, the task is checked or crossed off. The traditional method is to write these on a piece of paper with a pen or pencil, usually on a note pad or clip-board. Task lists can also have the form of paper or software checklists. Writer Julie Morgenstern suggests "do's and don'ts" of time management that include:  Numerous digital equivalents are now available, including personal information management (PIM) applications and most PDAs. There are also several web-based task list applications, many of which are free. Task lists are often diarised and tiered. The simplest tiered system includes a general to-do list (or task-holding file) to record all the tasks the person needs to accomplish, and a daily to-do list which is created each day by transferring tasks from the general to-do list. An alternative is to create a "not-to-do list", to avoid unnecessary tasks. Task lists are often prioritized:  Various writers have stressed potential difficulties with to-do lists such as the following:  Many companies use time tracking software to track an employee's working time, billable hours etc., e.g. law practice management software. Many software products for time management support multiple users. They allow the person to give tasks to other users and use the software for communication. Task list applications may be thought of as lightweight personal information manager or project management software. Modern task list applications may have built-in task hierarchy (tasks are composed of subtasks which again may contain subtasks), may support multiple methods of filtering and ordering the list of tasks, and may allow one to associate arbitrarily long notes for each task. In contrast to the concept of allowing the person to use multiple filtering methods, at least one software product additionally contains a mode where the software will attempt to dynamically determine the best tasks for any given moment. Time management systems often include a time clock or web-based application used to track an employee's work hours.