And that's 30 times you have to check in and out. Most of them don't charge much, but it adds up if you do, as we did, the chain in one season. Both in terms of time and money. Average time I would say was 4 hours times 30 check-ins. An investment in time if you plan a 7 month season.
Pick your favorite dreams and do em'. You are not going to see everything in every island in one cruising season. And if you try, you will be seeing customs officials instead of natural and cultural eye bombs.