Orphaned field rate
Share of custom fields not referenced by any report, page layout, automation, or integration.
unreferenced custom fields / total custom fieldsBenchmarkPractitioner finding: 20-40% of custom fields on a mature org are unused; target ongoing pruning to keep it under ~15%
Orphaned fields bloat page layouts, confuse reps into filling dead fields, and make every schema change a guessing game about what is safe to touch.