Also, with editors like vim, you can press % to go to the matching brace (curly bracket). In fact that works in vi too, right from the early vi days; also, in vim, if you position the cursor on an opening or closing brace, it momentarily highlights the other one (at least if that brace is visible on the screen, can't remember offhand if this works even if not visible).
When you refactor, yes. In python, say you add a new condition inside a condition, it's really easy to get lost and indent the wrong one to the wrong level.