It depends on whether people search for what the business sells, and that is checkable in about ten minutes.
How to check
Open Google’s Keyword Planner or a similar free tool and search for the actual service, in the actual area served — “plumber Kilimani,” not “plumbing services,” if that is genuinely how a customer would search. A near-zero result across every reasonable phrasing of the service means there is little to no search demand to capture, regardless of how good the eventual SEO work would be. A visible, even modest, volume means real demand exists and the rest of this question is about payback, not existence.
When the answer is no
Three situations where SEO is not worth pursuing, at least for now: no search demand for the actual service in the actual area, as checked above; unit economics too thin to absorb a months-long payback period before the investment returns anything, as covered in how long does SEO take to work?; or an existing referral or repeat-customer channel already running at full capacity, where more visibility would create demand the business cannot currently serve.
When the answer is yes
Real, checkable search demand for the service, an economics that can absorb a payback period measured in months rather than days, and either spare capacity to serve new customers or a plan to grow into it. A business meeting all three has a genuine case for SEO, independent of how urgently a provider might frame the decision.
What will this cost me?
The payback framing that matters: customer value, against cost of the work, against a realistic timeline. If a single new customer is worth [KES RANGE — MBOGO TO FILL] over their relationship with the business, and SEO work costs [KES RANGE — MBOGO TO FILL] per month, the question is how many such customers the work needs to produce, and over what period, to clear that cost — and whether that number is realistic given the search volume checked above. A business that has not run this specific calculation is deciding on instinct, not economics.
Is this for a business my size?
Size matters less than the three conditions above. A small business with real, checkable search demand, sound unit economics, and room to serve new customers is a better SEO candidate than a larger business missing any one of the three.