The sliding window technique is a common approach for solving problems that involve subarrays or substrings of a given size. Instead of recalculating values for every possible subset, you maintain a 'window' that slides across the input, updating the result incrementally. This is particularly useful for problems like finding the maximum sum of a subarray of a fixed size or checking for anagrams in a string. By reducing redundant recalculations, the sliding window technique improves efficiency and typically brings time complexity down to O(n) from O(n^2) in many cases.