Understanding how long it will take to generate results is one of the biggest questions anyone looking to undertake any SEO effort is going to want to answer. The challenge with this and many other questions is that there is no blanket answer. Each and every site has its own unique fingerprint in Google’s index and as a result all sites will perform differently.
A site with a long history in Google’s index that is currently held back by technical issues may see near instant results as soon as the issues are fixed. On the other hand, a site that is just beginning their SEO journey might take many months until the see meaningful results.
While the idea of a Google sandbox has gone by the wayside many years ago, there is still a concept of SEO needing to marinate within the Google results. It takes time for Google to crawl and index a new page. After that, it takes even more time to acquire positive signals like backlinks, performance metrics, and on-SERP click through rates.
Regardless, in nearly all cases I am certain that within six months nearly all sites will see positive momentum that validates their SEO efforts. The growth will be slow and hardly noticeable but when one looks back after a period of time they will always see a positive change.
SEO traffic is one of the slower channels to scale, but the investment is well worth it. My experiences helping to build SEO efforts from zero to millions of dollars has always proven out that SEO is the highest ROI channel by far!
The best of way of illustrating this is to think of a hike up to the top of a mountain. Progress will be slow and painstaking, and even after some time it may feel like the summit is still far away; however, if after an hour you look back you should see progress made. After 6 hours, the summit might still be far, but the progress will be undeniable (provided of course you did not get lost!)
One final note: don’t measure SEO progress in rankings; rather focus on the traffic and revenue that results from organic sources.