Originally Posted by AJ.
So I suppose to focus the question more. If you found two identical boats for sale both 12 years old and same engine hours but one with a full Suzuki service book stamped and the other with a load of receipts for service parts and the owner had carried out his own service at the correct intervals every 12 months or 100 hours. Would you expect one to be more desirable and to command a high resale price?
This kinda strikes me as a Lamborgini/Ferrari - which would you buy if....
The chances of finding either in your driveway are limited. To answer your question, what you save in service costs and dealer damage* will surely be more than you'd make at sale time.
*Dealers - Big Can O' Worms here with your name on it, open with caution