Protein A resin lifetime — how many cycles are you really getting?

Modern alkaline-stable Protein A resins are typically validated for ~100–200 cycles; older resins 50–100. Set your reuse limit from an actual resin-lifetime study (capacity + HCP clearance + carryover) at small scale, not the vendor max — the real limiters are fouling-driven capacity loss and carryover. A robust 0.1–0.5 M NaOH clean between cycles is the single biggest lever on lifetime.