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Generally, the large caps on the line side of a switchmode supply don't fail except from a lightning event or similar. They only handle 120 Hz ripple, as part of a voltage doubler. If they hold a charge, and aren't obviously leaking or bulged, they are doing their job.
The ones that get stressed and fail regularly are the filter caps on the secondary side. They have to deal with high frequency ripple, and heavy ripple currents. Their ESR is much more critical, as well.
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