I am probably "preaching to the choir" but there is often another 'elephant in the room' when considering a used boat. Power or Sail, similar problem.
That's "Deferred Maintenance". I realize that statistically a low % of used boats are fully maintained, but I know that some
are. Over the years I have personally known two of fellow YC members that always kept their sailboat UP-to-date. When they sold them they did get more return than most sellers, and more important got immediate buyers. Eager buyers.
Most used boats on the market have some significant or major dollars that were saved (i.e. banked and unspent) over the years by their owners. Then the owners want to sell and receive the money that they have already banked. Unrealistic and crazy and Illogical.
Waaaay back when we were shopping for our first real racer-cruiser "big boat", moving up from our trailer sailer Ranger 20, a surveyor friend told me how to assess the price and value of a used sailboat. Since so many were in need of major maintenance/upgrades, his advice was to assess the prospective purchase's immediate maintenance needs, assign a fair price to each item on that list, and then figure out the true offer price of that particular boat after all the work was done.
Subtract the price of what would actually be a turn-key specimen and then offer that purchase price to the seller. Not rudely, but firmly. Be prepared to write the check.
I soon found out that doing this would lead to "negative" offers where the seller would need to pay
me XXX number of dollars to take their boat!
Oddly, most brokers were quite sympathetic to our plan, and many admitted that it was quite difficult to list really clean boats. (!)
So when we found a pristine boat that honestly was "Turn Key", we bought it! The first owners had kept it super clean, and while the instruments were minimal, this had the advantage of us not having to repair or replace old parts. I recall that when we lifted an access board in the cabin sole and saw a clean and shiny bilge we were just SO impressed. A decade later we sold that boat quickly for a good price, too. It helped that we had been looking for a high quality boat, and after looking at HInterhoeller, CS Yachts, and Yamaha, knew to avoid low-end production boats; I had raced on a number of boats from the mass-market segment, and was aware of their design and build shortcomings.
The market now is different, but that might make it easier to buy a high-end boat worthy of restoration. I know the value of the older low-end boats is very very low. I note that, from reading the ads, high quality and better-designed boat have had their asking prices depressed down with the low-end stuff, which is helpful to a buyer looking for a good boat. I would call this a sort of "Gresham's Law" of boat valuation.
As for us, last time around, we always knew we wanted to own something really strong and fast, and keep it for at least a decade like we kept our previous Niagara 26. Having bought the EY-built Olson in 1994, we figure we have amortised out pretty much every $ we have put into it. But then, we Would say that!
Moreover, we have several friends that take two (or more) cruises per year for two weeks to a month, per. In a few years their "fun" expenditures add up to more $ than most sailboats! They end up with a flash drive full of pictures; big whoop.
Random philosophy bits dispensed, two cents, and not even worth every penny!