What should I do when a sponsorship ends or a brand can no longer afford to sponsor me?

Take the high road and be a professional. Appreciate what the sponsor did for you, understand that budgets change, ownership changes, and timing shifts - often they may still want the relationship but simply can't afford it. Your reputation follows you, and other sponsors will hear from racers in the industry about how you handled the transition. Being graceful when a sponsorship ends positions you well for your next opportunity, as potential sponsors will remember you as 'a class act' when they hear about how professionally you handled previous relationships.