The funds are probably the easiest to solve! In our case, John had the idea of a relatively early retirement in mind when he set up pension savings in 1981. Mo has always had a discipline of saving and these were invaluable. We were also lucky in investing in a house before the recent boom that we were able to improve and capitalise on, and which became an enabler for our other funding projects.
The sea does not take prisoners, and the skills required do have to be acquired over a period of time and in different circumstances. A classroom certificate is useful, but cannot substitute for experience. It is also necessary to have at least an understanding of the systems on a boat: nowadays these can be complex.
While you can make your opportunity, you have to be comfortable that you also have the space. Factors such as families, elderly parents, have to be taken into account. Will you need to return to work, and will this be possible? We are fortunate in taking early retirement, and do not have too many ties, but they are still a consideration.
The crew, if any, has to be a ready and willing participant! Leaving aside the problems of living in a small space, you must share (or be able to negotiate) the same objectives!
Finally, it goes without saying that you need to be sufficiently fit and healthy. The majority of cruising people are doing so in their later years where health issues can play a part, and ultimately may force you to give up the lifestyle (fondly known as 'swallowing the anchor'). We are not giving up, but of 4 seasons so far, two have been seriously impacted by health issues, with unforseen consequences in terms of finances. In 2005, John had a heart attack followed by surgery in the UK, and in 2007 an infection of the leg (cellulitis) requiring hospitalisation and a lengthy convalescence. In each case, there were implications for boat storage, travel, and accomodation expenses, as well as living expenses, that we had not planned for.