We have spent up to 5 months at a time on Wild Blue, our CD-25; pretty evenly divided at anchor and in marinas. We were moving most of that time, so we weren't able to take advantage of weekly rates at marinas. The marina rates vary widely, depending on the part of the country... pretty reasonable through most of the PNW, pretty pricey at the other corner of the country in the Florida Keys. Fuel use and cost is higher that when at home. Food is generally less, because we can't always eat lunch out (which we do when home). Even though our home is on a canal, there are intangibles that are hard to measure: time on the dock vs time in the cockpit.
In the boat, we have the "something in/something out" rule. You buy a new shirt, you have to toss an old shirt. Storage space is finite. And another consideration: we figured anything you do off the boat (shopping, laundry, running for parts) is going to pretty much eat up the whole day. It's more work to take the dinghy to the docks, hike a mile or more to the store, haul back 10 bags of groceries, load 'em into the dinghy, haul 'em up onto the boat, then put 'em away. That's assuming you're at anchor or on a mooring ball. A bit less work if you are in a slip. Even easier if you have a car or truck at the marina... a rarity for the kind of cruising we do. If you're covering big distances on land, you may have to use public transportation. We took our fold-up bikes on our Erie Canal/Trent Severn cruise last summer and got plenty of use out of them, even during our stay at Liberty Landing, the marina by the Statue of Liberty and across from Manhattan. Oh, it was real pricey there... and SO worth it.
The big deal with extended time on one of these small boats is the compatibility of the couple (assuming a couple, 'cause a single guy can put up with stuff his lady friend might not).
Visiting with folks who live aboard or full-time RV, you will find that their lives are not so different from when they were living in the sticks and bricks... if you eat out a lot, you will tend to do that also when your cruising allows. If you like internet connectivity, you will find a way to make that work on the boat. We generally don't watch much TV while boat cruising. We do spend more money on charts (paper and electronic) and cruising guides than we would if in our home area.
So, it's leading me to that old stand-by: it depends. You can certainly spend less than when at home, but if you are doing lots of touristy stuff, you can spend more... and justify it by saying, "Hey, we may never be this way again."
Unlike some folks, I am rarely anxious to get back to the house. In fact, that's the reason we have listed our house for sale: we'd rather be on the boat or in the RV.
It can be done, it can be good. Or, you might find out you don't enjoy THAT much togetherness. Some people don't like the unknown - where will we be able to resupply next? There's a nasty norther blowing in - anchor or in a slip? Everything you can do to make the boat comfortable for you both makes it easier to stay out longer.
I don't think I'd care to live on our boat in one fixed location for months at a time... when you're cruising, there is always something new to see and explore as you travel, making it easy to be out of the boat.
And then there's the inclimate weather. :shock:
Best wishes,
Jim B.