The used 10x30 I unwisely bought has films of moisture condensation internally.
It is old. 10 plus years. It works, but I don't like using substandard binoculars.
The question one has to ask is. (Not if one is feeling lucky. Clint Eastwood, but).
Do you want to use a binocular that has moisture condensation in the objectives, prisms, inside the eyepieces, in the electronics and in the stabiliser mechanism?
Or internal dust, as had an 8x25 that nobody on this forum apparently knew how to sort out (I did).
If a £10,000 professional Canon lens is brought in to Canon service U.K. no doubt they can strip it, clean every glass surface, reassemble and align to full standards.
Will they do the same with a 10x30 IS?
Maybe they are easy to strip down, clean and have electronics replaced. I don't know.
That is why they have 1 or 2 years warranty.
You get binoculars that completely outresolve any standard competitor but at the cost of complexity.
That is why I would not buy unseen used.
And the stabilisation has changed over the years, maybe for the better. So again old Canon IS unknown have little true value. If you want one, buy it new or fully inspected with great care.
A moistured or fungused IS binocular out of warranty is to me of no commercial value, unless Canon can indeed provide a full service, which it might on the 42 and 50mm.
In Hong Kong they strip everything and clean off the fungus. Those days are long gone in the U.K. although some have the patience to do it.
Cooke and TTH lenses have for 100 years been made to easily strip and clean. Not so most others.
Do you really want to buy an old fungused Olympus zoom lens? Or an old Nikon lens full of dust.
I don't.