Agree with Elizabeth, but if it were me I would remove the top and/or bottom cover and at least do a visual. If there is anything leaking from a cap, then I would consider replacing; if all looks well, I would give the interior a gentle blast of air to remove dust and not worry about the caps for several years. Indeed, ML amps are quite durable.
Durability of Mark Levinson 20.6
I've recently purchased ML 20.6 monoblocks from 1993, which has never been serviced. It is in perfect condition and in estimation of the seller has 10000 hours of operation. It still works perfectly. I wonder if I should replace any caps and other components after 15 years of operation?
Regards
Wojtek
Regards
Wojtek