You use time complexity and space complexity functions to compare the algorithm to others of a similar nature (one sorting algorithm to another sorting algorithm, for example).

Most problems can be solved by many different algorithms, each with its own demands on time and space. Complexity theorists sort problems into categories, ... and it’ll give you a new algorithm that ...

In its best case, where the list is sorted or nearly sorted, its time complexity is O(n). As far as space complexity is concerned, Insertion Sort requires O(1) additional space (for variable storage).

Design algorithms and analyze their complexity in terms of running time and space usage; Create applications that are supported by highly efficient algorithms and data structures for the task at hand; ...