It's not easy to get website traffic. Both paid ads and organic search engine marketing need to be fully optimized. Search engine optimization is the more crucial of the two, with a much higher potential return on investment.
SEO takes a lot of work, and a significant amount of time, to see results. Whether you're sticking solely to SEO or using paid advertisement alongside it, once your business has arrived at a great strategy that starts pulling in the visitors, you want to keep it that way.