Yes, you can absolutely do SEO yourself, especially if you are a small business with a tight budget and limited competition. Many foundational tasks, such as setting up Google Search Console, optimising your Google Business Profile, doing keyword research, writing blog content, and improving page speed, are learnable with free resources. The main trade-off is time, typically 10 to 15 hours per month at a minimum.
DIY SEO works best in less competitive niches and local markets. However, as your business grows or you operate in a competitive industry, the complexity increases significantly. At that point, bringing in an experienced freelancer or agency tends to accelerate results and free you up to focus on running your business. Start DIY to learn the basics, and scale up professional help as needed.