If your garden has a specific theme, it makes sense to buy lawn and garden accents that fit into this theme. Theme gardens are one-of-a-kind places where all the various parts support one single purpose. All the plants fit into that particular theme, and all accents and accessories (including containers and plant supports) should generally speaking also fit the theme.
Traditional examples of theme gardens include vegetable and herb gardens. More modern versions often include fairly exotic options such as nautical gardens and fairy gardens.
If you have such a garden it makes sense to purchase lawn and garden accessories that continue this theme. For a nautical-themed garden, suitable accessories could, for example, include a decorative garden lighthouse lantern or a mermaid kisses garden sign. For a fairy garden accents such as a fishing fairy boy will undoubtedly pique the interest of nearly every visitor.
The bottom line is that your lawn and garden accents should be as unique as you, and as such they should say something about who and what you are, about your interests and also about your dreams.