So many variables go into what a boat is worth. I payed a low going in price for my boat that took into account the fact that the boat had not had any maintenance since it was purchased in 1995. All of the rigging was original, instruments dead, motor not running but repairable, green hull and mast chalked, deck core moisture but no de-lamination, tiller rotten from the sun, head pump frozen, original sails and so on. On the positive side, little use, no deck crazing and the interior looked like a museum. The result of all of this is that after a proper rehab and a full set of Quantum sails, I am in the boat for more than the top end of pricing noted on this board. I also have a perfect boat that I really enjoy.
If you have kept up with the boat you should expect the high-end, it is worth it. If several of the systems will need to be replaced, major deck work is required and so on, not so much. I looked at a couple of other makes of boats that needed pretty much everything, 20 years of no investment, with owners that wanted the average asking price for the boat.