Most title tag advice stops at best practice. Running titles as an ongoing testing programme, rather than a one-time audit, is where the compounding returns are.
Pick the pages where a test can actually resolve
You need enough impressions to detect a change. Pages with fewer than a few hundred impressions a month will never produce a readable result, so testing them wastes the calendar. Sort by impressions, not by traffic — high-impression, low-click pages are the ones with headroom.
Control for position
Click-through rate moves with ranking position, so a title change that coincides with a position shift tells you nothing. Compare CTR at a comparable average position before and after, and discard any test where position moved materially during the window.
Give it time and change one thing
Four to six weeks per test, one variable at a time. Changing the title and the description together produces a result you cannot attribute. Recrawling and reindexing also mean the first week or two of data reflects a mix of old and new snippets.
Bank the pattern, not the page
The value is not the individual page's improvement. It is discovering that, on your site, question-form titles beat statement-form ones, or that including the year helps. That finding applies to the next five hundred pages you write, which is where the return actually comes from.