To keep your landing page/website's conversion rate fit and increase conversions further, we'd advise carrying out a conversion optimization audit at least yearly. If your business is focused on online purchases, we'd even say once in six months. Each time, you may see many new and exciting possibilities to improve conversions, but don't let the results of conversion audits overwhelm you. You can prioritize optimization efforts and implement just a few per iteration and still see your conversion goals reached.