The best way to determine if your website is the best it can be (currently), is to see how your customers interact with it. There are plenty of tools out there, like HotJar, that track in real-time where website visitors are clicking, where their eyes are looking, how long they are hovering over certain text boxes, and more. You can additionally see how well it is performing by way of SEO. Tools like Google Analytics and Google Search Console help web developers understand for free how their site ranks compared to the competition.