There is an easy answer to the question of why do SEO: because appearing on Google when your customer searches for you is better than not appearing. That answer is correct but useless. The useful answer is longer and has more nuance.
SEO has a bad reputation because many people have spent a great deal of money on it without seeing proportional results. And in many cases, they were right to be frustrated. Not because SEO doesn’t work, but because the SEO they bought wasn’t SEO. It was a service called SEO that consisted of things that in 2015might have worked and that in 2025are irrelevant or actively harmful.
This is the honest explanation.
What SEO really is
SEO is the process of making your website the best answer Google can give to a specific question. Nothing more. Nothing less.
That involves three distinct things that must work together: Google being able to crawl and index your site correctly (technical SEO), your site’s content being genuinely relevant and useful for the searches that matter to you (content SEO), and relevant websites linking to you because you are too (authority SEO or link building).
If one of the three fails, the whole thing falls apart. And all three require ongoing work, not a one-off intervention.
The financial argument nobody explains properly
When a business invests in paid advertising — Google Ads, Meta Ads — every euro generates traffic while it is active. When the budget runs out, the traffic disappears. It is effective for immediate results. It is inefficient for building long-term value.
What three components does a complete SEO strategy need?
A complete SEO strategy requires three components that work together: technical SEO so that Google can crawl and index the site correctly, content that is genuinely relevant and useful for target searches, and authority built through links and external signals. If one of the three fails, the whole thing does not work, and all three require ongoing work, not a one-off intervention.
SEO works in reverse. The first months of work generate little visible traffic. But content that ranks well in month six keeps bringing visits in month eighteen, in month twenty-four, potentially for years. The marginal cost of each visit falls over time. You reach a point where the organic channel brings you qualified leads at a cost per acquisition that no paid campaign can match on a sustained basis.
This does not mean SEO is always better than paid advertising. It means they have different time horizons. Paid advertising is the best option for results within weeks. SEO is the best investment for building your own traffic channel that does not depend on you continuing to pay.
When SEO makes sense and when it doesn’t
SEO makes sense when your clients are actively searching on Google for what you offer. If someone in Bilbao searches for “gestoría para autónomos Bilbao” and you are a gestoría in Bilbao serving self-employed people, that is exactly the type of search that SEO can capture for you.
SEO makes no sense —or makes far more limited sense— when your product or service is so new that nobody is searching for it yet, when your market is so small that search volumes are marginal, or when the sales cycle is so long and complex that organic traffic rarely converts directly.
There are also sectors where SEO competition is so intense and the dominance of large platforms so overwhelming that a small business has very little chance of appearing in the most valuable searches. In those cases, the right strategy is to focus on niche searches where competition is lower, on local SEO where the geographical factor acts as a filter, and on content that ranks for specific questions that the large platforms do not answer well.
Why results take time to come
This is the part that causes the most confusion. SEO does not work in weeks. Significant results —ranking improvements that translate into relevant qualified traffic— appear between the third and sixth month of continuous work in most cases. The impact on leads and sales tends to materialise between the sixth and twelfth month.
There are technical reasons for this. Google needs time to crawl changes on the web, to process new content, to update its index, and to assess how domain authority shifts as new links are acquired. The algorithm does not update its assessment of a domain in real time: there are update cycles that can last weeks.
When does investing in SEO make no sense?
SEO makes limited sense when your product is so new that no one is searching for it yet, when the search volume in your market is marginal, when the sales cycle doesn’t go through Google, or when you’re competing with large platforms that dominate the most valuable searches. In those scenarios, it’s better to prioritise other channels before investing in organic search.
SEO is also cumulative. The effects of the first months of work build on those of the months that follow. A well-executed SEO strategy over one year does not produce the same result as twelve months of poor SEO: the effects are not linear.
The most expensive mistake: starting and stopping
There is a trap that many businesses fall into. They invest in SEO for three or four months, see no spectacular results, and abandon it just before the effects would have started to accumulate visibly.
This is a problem of expectations, not of SEO. If someone promises you visible results in the first month, they are lying or they do not understand how the channel works. If nobody explained before you started that SEO is a minimum twelve-month investment, the agency failed to set the right expectations.
The right question to ask when evaluating whether to continue with an SEO strategy is not “are we already in first position?”. It is “are the positions of the target keywords improving month on month?”, “is the number of keywords for which we appear on the first page growing?” and “is organic traffic improving even if it is still small?”. If all three answers are yes, SEO is working. The results in the form of leads come afterwards.
The short answer
Frequently asked questions
What type of business does SEO work best for?
SEO works especially well when your customers are actively searching on Google for what you offer and when you can sustain an investment for a minimum of twelve months. It is ideal for local businesses with clear search intent, professional services, and companies that want to build their own acquisition channel that does not depend on a monthly advertising budget.
Do SEO if you have a business that wants customers from Google within the next twelve months and is willing to invest in a sustained way to build its own traffic channel. Don’t do it if you need results this week — that’s what paid advertising is for — or if your budget won’t allow you to commit for at least twelve months.
How to tell if an SEO strategy is working before you see traffic?
The right question is not whether you are already in first position. You need to assess whether the positions of target keywords improve month on month, whether the number of keywords for which the site appears is growing, and whether qualified organic traffic is increasing, even if only slightly. These indicators anticipate the visible return before traffic takes off.
SEO done well is the digital marketing investment with the best long-term return. Done badly or poorly executed, it is a way of wasting money with a very good narrative.