My boat, a +40 year old Alberg 35 might bring $30,000 on a good day. If I spent another $12 to $14,000 (or more) on the decks it might fetch $35,000 from the right buyer. Several years ago while renegotiating the boat's value with my insurance company I documented over $50,000 in upgrades over and above the purchase price excluding any of my labor and annual maintenance items. As I said above, those are numbers that I'd rather not dwell on but the boat suits us fine and it has served us well for the past 16 years.