Score every page on 4 axes
Traffic (last 90 days), backlinks, conversions, and freshness. Pages with zero on all four are deletion candidates. Pages with one or two might just need a refresh.
Refresh: the default action
If a page has any traffic or links, refresh it before deleting. Update stats, add new sections, improve depth. Republish with a new date. Often doubles traffic.
Merge: when two pages overlap
Combine into one stronger page, 301 the loser. Preserves backlinks, consolidates authority, fixes cannibalization.
Delete: only when there's nothing to save
Return 410 (Gone), not 404. 410 tells Google the page is gone forever and triggers faster de-indexing. Don't 301 a deleted page to an irrelevant one — that's a soft 404 to Google.