My first TA (14 nights Port Everglades to Copenhagen) was supposed to be 6 sea days, stop in Azores, 2 sea days, Southampton, then I think the remainder was port days.
When I booked, I wasn't sure how I'd like 6 sea days in a row, but it turned out to be 9 sea days in a row, since Azores port was closed when we arrived due to bad weather. So, after that experience, I was comfortable booking a 10 night non-stop and later two 8 night non-stops.