Buying used vs new?

I bought my Pass xp10 used at half price.  I love it.  I think it depends on the quality and reviews of the initial product.  Then the age.

I agree with jgoldrick.  I'd add that if it's a current model, that's even better.  The only caveat is that if you are purchasing a tube power amp, the tubes on the power side wear out the fastest and might be expensive to replace...so I'd factor that in.  Most people I know who enjoy tube preamps get a lot of life from those tubes.

I personally would shy away from purchasing a dealer demo unit, as they have many more hours on them, compared to one which is owned by an individual.

I'm hesitant to purchase pre-owned speakers, as I find it's oftentimes difficult to identify whether they have been abused by the previous owner.

Absolutely. No moving parts. The preamp is the heart of a system. So leveraging your purchasing power by buying used is a great way to go. A good preamp will last many decades… Actually I have the first integrated amp I purchased in 1972. Still works.