The results of SEO services are organic and for the long haul. However, some gains can be picked up on the way. Nevertheless, it is complicated to ascertain a time frame for the results to be visible, as they rely on multiple factors and the definition of results from a customer perspective.
As a starter, SEO does offer immediate results in terms of better content and user experience. However, the key result anticipated by most is to rank at the top of searches. This relies on website design, domain age, meta descriptions, competition, baseline traffic, geographic location, target market, etc.
SEO experts provision for a timeline ranging from 4-6 months for the results to show up. SEO results grow over time, i.e., results at the end of one year would ideally be better off than a short time frame of 6 months and tend to grow prospectively. However, it is key to continue with SEO services for continued growth.