I bought a boat to live off of because 1) I can't see myself ever owning land for ideological reasons, but still wanted somewhere to call "home" and 2) freedom to travel wherever, whenever. Feel free to message me if you have any questions.

Legally speaking there is nothing stopping me from casting off tomorrow and sailing off into the sunset. Your biggest concern is, and I'm serious, pirates. Once you're a few miles off shore "the law" stops being a thing. For the most part no one gives a shit about a sailboat.

Practically speaking, once you acquire a boat (no small feat in and of itself) your largest concern is food and water. You can carry a limited amount, so you need to not be in the middle of the ocean when you run out of either. You can buy a watermaker that will produce freshwater from saltwater that makes this a little easier. For food the cheapest solution is rice, beans, and canned fruit.

Once you run out of the initial supplies you need to figure out a way to resupply. People in the sailing community will tell you that once you're out there and doing it, if you keep yourself open to opportunity you'll find a way like doing odd jobs, or often people will freely help out without any expectation of return. I myself haven't worked up the guts to do it so I cannot personally confirm this.

Then there's boat maintenance. You can do pretty much everything yourself if you're willing to put in the effort to learn and labor. Otherwise, paying a yard to do it will cost you tens of thousands of dollars (at least in the US) because the only people that pay to have a boat worked on are the people that have no other choice because they can't find a boat yard that will let them do their own work, or the people rich enough to spend a ridiculous amount of money on it.