Affiliates can earn from existing users who upgrade on BMF.io if those users are linked to their referral account and the upgrade qualifies under the affiliate terms. Tracking referral activity, upgrade conversions, and commission reports helps affiliates understand which users continue engaging after signup. Looking at customer behavior, such as plan changes and recurring payments, reveals the long-term value of referred users. Clear attribution systems ensure affiliates receive credit when their audience moves from a free or lower-tier plan to a paid upgrade.