It's a no-swap for me, unless the old capacitor does have visibile mechanical degradation such as cracked rubber seal. I've found this situation on big Philips capacitors: still totally fine electrically after 40-50 years, but they probably will not stay so for long because the moisture barrier is compromised. New capacitors that have been on storage for years will improve esr and Vloss after a few hours. If the supposedly new capacitor with abnormally high ESR or Vloss is a small inexpensive one, I discard it and I buy a new batch. Sometimes I've received such aged capacitors from reputable distributors, but they take them back when I complain
