Plan on 4–6 months before measurable movement and 8–12 months for significant results. That range is consistent across practitioner guides, and anyone promising page one in 30 days is selling something other than SEO.
Local SEO moves faster: Google Business Profile and local-pack improvements often show in 4–8 weeks, because the local signals (profile completeness, reviews, citations) respond quicker than sitewide authority does.
New sites take longer than established sites with fixable problems. The practical takeaway: judge SEO on a 6-month clock with monthly checkpoints. And get the compounding started sooner rather than later, because the clock doesn't start until the work does.