My husband and I have been cruising since 2003. Pretty much every year since then, we have taken at least one trip.
We are 55 and 66 respectively. Hubby retired and I work for myself so have a lot of flexibility to travel.
Initially, we loved cruising for the fact that it is the most cost-effective vacation on a per day basis (he's an accountant)... we enjoyed visiting various ports and taking excursions that allowed us to get to know more about the port, nature, and history of the area.
In 2014, we had a couple medical catastrophes so our ability to take excursions was substantially reduced. Now, the ship and our cabin has become that much more important. Health issues aside, we still love cruising and have 7 cruises already booked for 2015... kind of thumbing our noses to illness and taking the YOLO approach.
Carpe diem folks!