A/B Testing is one of the most powerful marketing tools we have. In essence, it is a simple way to test changes to your website against the current design and determine which ones produce better results. It is a method to validate that any new design or change to an element on your webpage is improving your conversion rate before you make that change to your site code permanent. For instance, you may want to change the color of a button here, increase the size of an image there, use a different layout, or simply address to your clients using different registers.
But don't be mislead! A/B Testing is not only a tool for modifying the look and feel of your site, but a fantastic way to learn a lot about your site and your business. We regard A/B Tests as a learning tool for the business owner. Just thinking about possible tests gives you a perfect excuse to reconsider your business assumptions and offers a low-risk approach to test alternative approaches that, otherwise, you would have never dared to try. And if the test "fails" (meaning that your current version doesn't need to be changed) you should even be happier! Failed tests are as useful as successful ones—they allow you to get rid of possible scenarios that now you know for sure wouldn't work.
We recommend you always optimize your site. Keep in mind that, in the end, even if some optimizations may only bring a small improvement, they add up so the overall effect may well surprise you!