Cells should ideally be passaged during:
Growth curve of cultured cells comprises lag adaptation, exponential log proliferation, plateau where division balances loss, and death where loss predominates. Ideal timing for passaging aligns with transition from late log to early plateau when cultures achieve sufficient density providing high yield of cells for splitting but before deleterious effects of overconfluence arise. At this point confluence typically 70-80% for adherent fibroblasts and epithelial lines, or suspension density half of maximal sustainable concentration, providing many cells yet maintaining health with active DNA syn
Ref: Freshney Ch.14 Passaging at plateau late log; Alberts MBoC Ch.17 Growth regulation subculture timing before overconfluence stress.
