When the marketing team expresses a need for a new field to track ROI, the BA should explore existing Salesforce functionalities before customizing. Salesforce provides robust features around Leads, Campaigns, and Opportunities that can potentially track marketing efforts and their outcomes. By asking follow-up questions, the BA can understand the specific requirements and assess whether these can be met with standard features, which is often more efficient and sustainable than adding custom fields. This approach aligns with Salesforce best practices of leveraging out-of-the-box functionality to meet business needs, ensuring system simplicity and maintainability.