Choosing the boat
Hal Roth wrote a very readable book, "How to sail around the world". It appealed because, for every aspect of the endeavour, there are very practical tips. Everything is presented 'black or white' leaving the reader in no doubt as to the best solution. His advice on choice of boat was simple: the length should be between 38 and 45 foot. Any shorter and the extra weight associated with a RTW live-aboard would make the boat float too low in the water compared to what the designer intended. Any longer and you would be 'at the wrong end of the bay', drawing too much draught, mixing with the larger boats with professional skippers and missing out on the interaction with more well-heeled, like-minded sailors which is such an integral part of the RTW adventure.
His book dates from the 90's and, today, some might extend the upper length slightly. But we took this on-board as a key part of the selection criteria.
There are an endless list of possible selection criteria (material for the hull, is a skeg rudder essential?, size of tanks, etc). However we will consider just two on this site: catamaran versus monohull and budget versus age....