An eCommerce SEO timeline is most useful when it separates implementation from search response. The work begins with technical discovery and deployment, then moves through early crawl and index coverage, meaningful search visibility, and sustained commercial contribution.
Those stages can overlap, but they should not be treated as the same milestone. Large catalogs add dependencies such as faceted navigation, product and category templates, internal linking, rendering behavior, redirects, canonicals, and the pace at which development changes reach production.
That makes a single promised date misleading. Instead, use the ranges on this page as planning windows, record what was actually shipped, and judge each stage with evidence appropriate to that stage.
For budget alignment, the eCommerce SEO cost guide provides the related investment context while this page focuses only on timing and its dependencies.