Use break to exit when continuing is pointless. Searching for a value? Break when you find it. Detecting an error condition? Break to stop further processing. Example: for (int i = 0; i < 100; i++) { if (i == 50) break; cout << i; } prints 0 through 49, then exits at 50 without printing it.
Break skips both the update and condition check. The loop exits immediately, and execution jumps directly to the next statement after the loop closing brace.