@Craig683 Taking months-long bookings means you get less reviews. The Superhost criteria is 10 bookings during the 365 days prior to the quarterly Superhost assessment or 100 days booked over 3 reservations.
You also need to maintain a 4.8 rating. So if you, for instance, had 3 bookings of this length over the course of a year, and one of those guests left a 4* review, you would not make Superhost. Whereas if you only took short term bookings, and had 50 5* reviews, one 4* wouldn't bring your rating down much.
But as Andrew said, don't get sucked into thinking Superhost status gives you some huge advantage. It does not seem to affect search ranking to any great extent. Hosts who have had that status, then lost it, say it had no noticeable affect on their bookings.