I added up, roughly, what I spend on Blue Note's essentials yearly: 1200 for a slip, 1400 for insurance, about 2000 on haulout, storage, bottom painting (I'm with Karl on this one, I will not touch the stuff any more, it's too damn toxic), about 1500 on fuel. That does not include the surprises, as noted above, and the things that I buy for the boat that I decide to improve or change out. I don't have boat payments (this is one of the virtues of keeping the same boat for years- after a while, the payments stop). It seems that given that it also functions as a second home, as occupational therapy, a place to entertain friends, and a means for traveling to areas that are difficult if not impossible to reach any other way- that, all things taken together, it's not an expensive indulgence.
Like most of us here, I do much of my own work, and keep a careful eye on the rest. I am fortunate enough to have honest and skilled people available, for the most part, to do what I can't. I find that the biggest expenses are the "optional upgrades"- for example, last year 1200 for new carpet, 2000 for a new salon table (yes and worth it believe me), 1100 for the depthsounder upgrade for the Northstar 6000i. And 2300, I think it was, for the wiring upgrades which have been a huge improvement.
As the years go by I find that the huge upgrades and refits are fewer and less expensive. Maybe the lesson in this is that keeping the same boat for a long time is the best boating financial strategy of all, if you start with a good one. Which is, when you think about it, how we all got here to begin with.