How do I keep my SEO and paid search working over time?

You have built something that quietly works: the right people find you, at a cost that makes sense. That is not common. Plenty of businesses pour money into search and get noise. You have tuned it to bring signal, and that took real attention. The ground under this shifts constantly, though. Search engines change their rules, competitors bid up your words, what people search for drifts with the seasons and the years. A setup that is humming today can slip without any single dramatic failure. The danger for someone doing well is simply not looking often enough. So keep a light, regular check. Once a month, glance at what is bringing traffic and what each customer is costing you, and adjust before small drifts become real losses. You do not need to rebuild what works. You need to keep watching it, calmly, so it keeps working.