There’s no easy or definite answer in this sense. As a general rule, SEO is a long-term investment and should be seen as an on-going effort or strategy rather than a one-time job. This is because search engines look at hundreds of factors when “deciding” which websites deserve to rank for certain keywords, but also because nothing truly good comes out of a one week of work; good content requires research, internal linking requires time and attention, auditing the webssite & creating technical solutions takes expertise and time, and earned backlinks don’t just emerge over night. As a rule of thumb, an initial SEO campaign should be run (especially when it’s part of a larger PR campaign) for at least 6 months to see some serious results. Since every website is unique, every client’s needs are unique and not all countries use the same search engines, things can easily get complicated and require patience and plenty fo work.