A/B/n testing is the proven way to go whenever you wish to quantify the results of your ideas and their effect on your users.
In the above A/B/C test, modernizing the design of the join form resulted in 3% uplift in conversion for variant “C” and 4% for the winning “B” variant.
In this example, two different variations of a promo banner were ran early during the sale. Consequently, all traffic for the rest of the promotion was switched to the better-performing “B” variant. This resulted in an estimated 18% increase in profit for that particular campaign.