Query performance primarily depends on the amount of data scanned. If queries remain selective (e.g., filtering by tenant ID and a truncated date range), Firebolt only scans relevant slices, keeping query times stable as data grows. Broad queries (e.g., SELECT * over wide date ranges) will naturally slow as more data must be scanned. Best practices include indexing on commonly used filters, leveraging caching, and avoiding unbounded queries to maintain good performance over time.