I worked at a broadcast radio station that had been in service about twenty
years and we were starting to get random failures in the capacitors in
timing circuits. These capacitors had been in service for the full time
that the station was on the air and the station was a 24/7 operation.

I would vote on replacing the capacitors and still doing the gradual in-
crease of the input voltage. Normally it doesn't really help to do that
but there have been rare cases where a new capacitor surprises the new owner
with a loud bang.