The standard pattern: month one is a beautiful audit. Months two and three look productive: technical fixes, content briefs, a sense of momentum. Months four to six, the content pipeline starts feeling repetitive. By month nine, the agency is sending you the same four-page Looker Studio dashboard, ranking screenshots have replaced the strategic conversation, and you are wondering whether SEO is even working for your business. You drop the retainer and try a new agency, who runs the same audit you already paid for last year.
The fix is not a different tactic; it is a different cadence. Weekly Search Console review (so issues get caught early). Monthly content refresh queue (so old content does not silently slide down the SERP). Quarterly strategic review with a real human telling you what is working and what is changing. Reporting tied to revenue rather than rankings (because rankings are noisy and revenue is the only metric that decides whether the retainer keeps its budget).
The other failure mode is generalist SEO on a specialist platform. A WordPress SEO retainer running on a Shopify store will miss most of the issues that matter. A Shopify SEO retainer running on a WordPress site will miss most of the plugin-driven schema duplication. Platform-specific SEO knowledge compounds; we run dedicated pages for the platforms where we have it (Shopify, WooCommerce, WordPress), and we will tell you in the audit which is the right starting point for you.