You got some good insights there. So, it's better for me to get a Duc which has high mileage compared to a very low one? Have no idea how was it stored. Wouldn't the bad things show up the moment the bike will be started and ridden? The dealer says no test pilots but would start and ride the bike himself and take it to the freeway with me following and observing. I know that its not the best thing for me to know if it rides good, but at least would hear and notice if something is off with the bike. Thanks.
At least medium mileage. I wouldn't want to buy anything that has less than 1000 miles (1600 km) per year on it average. That's not just for a Ducati, but for any bike (or car). The more I deal with machines, the more I think that sitting unused is the worst thing you can do to them.
And the problem is that, no, the bad things don't show up right away. A rotted fuel line might work for a while before the vibration and unaccustomed use makes it let go. A dried out gasket might be OK for a while, before it starts leaking oil. If it starts right up and rides well, that's good, but it's not the whole story. And things like unusual vibrations from flatspotted bearings, tires, etc., or poor operation of controls from unlubricated cables, or twitchy switches from contacts that have corroded from disuse, wouldn't be obvious if you weren't on the bike; you won't catch those by watching.
All of these things might be fine. But they also might not; it's a gamble. I once dug a 15-year-old Honda literally out of a pile of garbage and leaves, where it had been for at least 5 years, rattle-canned it black, and got it running just fine with a few rubber bits and tires and cleaning. Then I put a few thousand miles on it without any real trouble. But I didn't count on that happening. And my total investment in the machine was less than $500, so I didn't care too much if it didn't work out.
Others may disagree with me, and I'll admit I'm at the far end of the spectrum here (with my M900 that's about to turn over 250K), but I'm way less afraid of high miles than I am of storage and disuse.