Final answer:
Story points are used to estimate user stories, and ideal time or elapsed time is used for task estimation, both crucial for project planning.
Step-by-step explanation:
Story points are commonly used for estimating user stories, and ideal time or elapsed time is used for estimating the tasks needed to complete a user story. While story points measure the complexity and size of a user story, ideal time represents the amount of work time required to complete a task without any interruptions. Understanding these concepts can greatly assist in the practice of estimation, improving the accuracy and efficiency of project planning in software development or other project management contexts.