Annual maintenance costs vary widely from one owner to another even for an identical boat. Some costs are relatively fixed, other highly variable based on annual hours of running. As others have noted, there are prior posts in the T&T archives....but one way to get an approximate handle might be to estimate each of the following you wish to include. (a)Marina costs...summer ....winter...winterizing & oil changes, electrical costs,esp a/c (b)Annual or bi annual haulout..painting of bottom, zincs (c)Fuel costs ...highly variable depending on annual running hours and cost/gal (d)Upgrades...figure material costs at $100/ft as a guide,minimum, perhaps higher for bigger boats, less for smaller..dependent on age and quality of original equipment...how much you do yourself. Figure installation (labor) costs about the material cost of the equipment... (e)Repairs..highly variable depending on equipment, local labor rates and your ability to do preventative maintenance (f) Opportunity cost...how much it costs you to invest in a boat rather than an appreciating asset...and/ or mortgage expense after taxes if you borrow to play "Captain". (g) Insurance....liability a required minimum in many marinas, full coverage a good idea for the first year or two... (h) Survey costs during initial purchase, (i) Spare or special equipment for passagemaking...hoses, toilet and pump rebuild kits, spare injectors or spark plugs, second GPS, radar, watermaker, extra anchors and lines..... (j) purchase, operation of a tender,outboard, davit, registration... If you have to pay for all work, it gets expensive very quickly. There are many tradeoffs possible...For example, since retiring I avoid about $4,800 summer marina costs in NY, but spend $3,500 of that amount for fuel while cruising for the six months...I always anchor out or pick up a spare mooring...so I gain a great deal of freedom but incur some "wear and tear". Haulout and bottom painting is now about $2,200....so I have been doing it every other year....Maybe I use an extra $100 of fuel in the second year because of a less clean bottom?? Run your engines at moderate, not top, RPM...greatly reduces unnecessary engine wear and improves fuel economy...Plan to minimize running an on board generator....and apply proper load when doing so....say 80% of rated KW... Repair example: This past spring I noticed a main engine salt water pump dripping...about a $1,000 job...Forecast was for three days of wind and rain, so I stopped in DN Kelly shipyard in New Bedford, removed the pump myself, about 1.25 hrs work, asked the yard to rebuild the pump with my parts, and reinstalled the pump myself, another hour...The yard charged me $130 for their labor. Parts were about $475 which I carried aboard...I realized this pump had been leaking the prior year, but decided to get it fixed because I don't like potential problems like that...Resued the impeller which I had replaced (myself) only six months ago saving about $80 for that item.... Engine Oil change and winterizing: Costs about $600 for my boat....I do it myself or more recently have been leaving heat on all winter...heater uses around 150 gal diesel fuel during the winter season....Don't know how??: watch a pro do it once, then do it yourself... Anyway, if you have a boat for seasonal weekend use plus a week or two of vacation, the daily cost is very high...if you live aboard and or can cruise much of the year, the daily rate can be far more reasonable... If you are buying a ten to 30 year old quality boat, say 30 to 60 feet or thereabouts, excluding opportunity and insurance costs, figure "maintenance" items above at perhaps an additional 15% of the price for the first year, maybe the second, then perhaps closer to 8% to 10% after ther initial "binge" purchases subside....Boost these if you don't do any work yourself...Reduce these if you exercise self control. One advantage on a boat is that the waterline sinks as you make additions, and room is limited, so you have to either stop buying new stuff or replace old stuff after a few years. One way to keep new equipment purchase costs in check: use the boat before making major changes/purchases to be sure they suit you, plan in purchases in advance so you have time to purchase from e-bay or purchase at the best price from "discounters", do as much of the installation as possible youself....saves 40% to 100% of the purchase price...Sell stuff on e-bay that you no longer use....If you can, stay aboard a prospective purchase as long as possible to see if you really like it...buying the wrong boat is very expensive... Rob Brueckner Hatteras Yachtfisherman