How long does it take to notice the results of an SEO campaign?
The thing we noticed is that the fastest changes, even after just 3-4 days, are the changes in technical nature. That means that if your website has any issues of this type, it would be best to deal with them as soon as possible. These problems are mostly solved by making changes to the coding of your website.
If we are talking about the changes in content or adding entirely new content, changes in rankings depend on the popularity of your website, meaning how fast will Google take that content into account. A good example is news websites, whose content appears in Google search results after just a few minutes.
Presentational, shops, or similar websites mostly have a period of 2-3 months during which Google and other search engines still decide which position is most stable among your entire content and for which keyword.
Of course, everything depends on multiple factors.