First GMP facility — what trips people up most in validation?

The tech is rarely the problem — documentation discipline is. Classic trips: (1) data-integrity / ALCOA+ gaps in logbooks and spreadsheets; (2) under-scoped change control; (3) treating validation as a one-time event instead of a lifecycle (continued process verification); (4) supplier/qualification paperwork lagging the build. Lock your quality system and CQA/CPP definitions before chasing equipment qualification — auditors follow the paper trail.